Coolant Bleeding


ben

New member
Good day to you all, (87 Westy)
I think that subject is worth a new topic, yours to decide.

Last year I changed my head gasket (another subject!!!), and of course; I add to refill my coolant system (with new one!). At the time I was not really aware of the "refill-air pocket" problem, if a problem! (But I was amaze by the complexity of the Westy cooling system), so I proceeded as I usually (no need to explain usual procedure) do with other car or motorcycle. By reading the coolant section of the Bentley, I found that there where to bleeding location: the front radiator and the thermostat, so I proceeded without lifting the van (did not know this method at the time, but it make sense now). The conclusion is I did not have any overheating or air pocket what so ever, I even don't recall adding some coolant later!!!
Lately, one of my friends that live in NB add is eye on an 87' Westy (like mine) after numerous e-mail and phone "tips & advice" exchange he finally bought it. (Thanks to this site also, he told me that he printed over 60 pages of this extremely fantastic forum to help him in his decision). To cut that short, he proceeded with an overall "refresh" of the cooling system, including the pump, heating valve, thermostat, radiator and many hoses (I should have done those also last year!!!! When changing my head gaskets), when he was finish, he started the van and proceeded like I have done on mine. (I sent him copy's of my Bentley pages on the subject, he has one now!!!) I also told him to read Capt. Mike well written "Tips" on the subject whit the following quote from Capt. Mike for reference:
Quote:
"""Later Vanagons had a pretty fair self-bleeding system - that tube around the top of the engine compartment. Bleeding at the heater cores is rarely needed; and messy to boot."""

He called me 2 days later and tell me that the van overheat (it was not doing that before) and he probably have some air pocket stuck somewhere (He is a pretty good agricultural mechanic). So he proceeded whit the lifting trick (no exact details for now), the problem disappear!!!, the van is running strong and at the right temperature. This post is only to show that 2 same vehicles have 2 different needs regarding the bleeding procedure, maybe he add some clogged hoses or tube but it appear to me that the 86 over new bleeding system is not perfect.

As I prepare myself for the same job this spring, I add a good look at my "self-bleeding system" yesterday and I still wonder a bit about that strange system, apart of the "high gravity" that it procures. I hope this tread will get more post so anybody who as question or answer can put is share of experience.
Regards to you all, Ben
 

Capt. Mike

Moderator
Just thought I'd had my most recent experience.

I changed coolant on my '90 -- an every 2 year regimine for me. The nightmare was getting to the drain plugs since you have to remove the protective sheet metal under the cylinders. My left, which has the remote mount oil pressure sender line running through it is the worst. (I have an auxiliary oil pressure guage.)

I have drilled a tiny hole the size of the 6mm allen head of the drain plug directly underneath. I still have to drop the sheet metal, but now only a couple of inches to see the drain plug, insert the allen wrench and remove it for a NEW seal. At least I don't have to break the oil line to the sender.

I opened the bleeder on the radiator, raised the front as high as my shop floor jack allowed, and opend one side -- drained most of the fluid there. Drained the other side to get the amount in the engine jacket.

My past measurements indicate I get about 10½ quarts of the 18½ of my system this way. Since I'm changing every 2 years and the coolant was clean & still tested full protection, I didn't do a full flush as described in the TIPS forum.

I then filled until I had flow out of the bleeder on the thermostat. I then lowered the front to the ground (rear still on jackstands) and filled until I had flow out of the radiator bleeder. Leveled & topped off both tanks.

I then took it on a 10 mile (up & down hill) run and noted the refill tank had dropped an inch. 2nd 50-mile major run in 103°F road temps with A/C a little later with no overheating -- gauge stayed its normal dead center. Refill tank dropped maybe another ½".

Two notes: :cool: First, the radiator bleed screw (and presumably the others) has cut-outs IN the threads for fluid flow around the bolt. The seal is the flat head against the tank body and is solely a function of the seal washer. Thus the requirement to change EVERY time you change coolants. Tightening the bleed bolt more does NOT seal the thread cut-outs. And since the threads are a metal insert molded into a plastic tank, you are asking to break the tank. Yes, the 8mm (on mine) copper seals aren't common but blow a $ at the dealer and keep a few on hand. You need 3 for a coolant change.

The 2.1 does have an extra bleeding vent system not on the 1.9. But that up & down hill ride works wonders for both.
 
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BobbyJoe

New member
My Westy, 1990, Westfalia, After changing an elbow, two thermostats, seals, clamps, etc. The coolant in the refill tank keeps going down after runs of an hour or more. Sometimes right away and sometimes after it sits overnight. The work was done by a local VW dealer here in Germany so you would assume they would know what to do. I need help so as to continue on my vacation or ship it home to the USA.
 

Capt. Mike

Moderator
Transferred to consolidate similar topics.

A. Cooper Member posted September 12, 2002 04:01 PM

Mike Robinson wrote:

"How have you found bleeding the cooling system? I find it a pain having to continuyally bleed it. Do you find after going up lots of hills the engine gets hot?"

A. Cooper wrote:

Mike, having recently performed a complete flush-and-fill on my diesel Westy (six drains, six fills), I've done a lot of bleeding. I followed Capt. Mike's sequence posted under the COOLANTS thread; although written for the waterboxer gas engine and cooling system, it's similar enough to the diesel to be very helpful.

I found the bleeding is best done with the front of the van jacked up 12-18". Open the bleeder valve on the top of the radiator until you have a steady stream of coolant flowing out, then tighten it down. Drive up and down a couple of steep hills to slosh loose any remaining air bubbles, jack up and bleed one final time. That's it.

Once you've expelled all the air from the system, it should stay out. If you need to continually and repeatedly fill and bleed, that suggests you're somehow getting air into your system. One probable cause may be a leak in a hose, radiator, or gasket that allows air to be sucked into the system during cooldown. Or perhaps you've simply allowed the coolant reservoir hidden behind the license plate to run dry. Or perhaps a dreaded head-gasket leak(!) is pumping air and combustion gases into a coolant passage in the engine block. You need to determine where your coolant is going and how the air is getting in there.

Any time you strain the motor with high speeds, hill-climbing, or hauling a heavy load, your operating temperatures will rise. But a well-functioning cooling system should be able to handle nearly anything. Under normal conditions my temp needle stays almost centered in the gauge. It might rise a little with city driving or a long climb, but quickly returns to normal.

Contrary to your experience, the mechanic whose services I sometimes use says the VW diesels typically run COOL, and claims his radiator fan has only kicked in once or twice in five years!

Good luck finding your leak, and let us know what you find.

A. Cooper

Mike Robinson Member posted September 13, 2002 10:54 AM

Cooling Diesel

I find the temp gauge very sensitive and I am sure I am somewhat paranoid!

When travelling on the flat 100km/h the gauge sits steadilty on the right hand side edge of the led, further to the right (slightly) (hotter) at 90km/h.

two thoughts - I know the gauge is not an accurate temp indicator so a variety of positions may be normal. Secondly at higher speeds the water pump is pushing more water - could I have a worn pump???

Bleeding does not make a huge difference. To the gauge position.

Going up significant hills causes the temp to rise, but it lowers when I go down into third - again - is this better water pressure from the pump again?

Going down the hills, no great load on the engine and the gauge will sit on the led.

I heave recently done some really significant hills and the gauge will approximate 'normal' ie over the led - going up! go figure.

I do not see a leak anywhere, but bleeding usually adds 500ml of coolant. I do smell antifreeze when I engage the heater and occasionally - usually the first stop of the day the cooling system pukes some coolant from the expansion tank - not the overflow which remains very constant. New cap on order, old conention pipe about to be replaced.

I have fulshed and replaced the thermostat.

No white smoke out the back. Performance is good engine rebuild by previous owners 20,000 km ago. 250,000 on the beast (no signs of a replaved water pump in the service history)

Earlier this year I have had the temp rise that the led flashes - up a BC logging road (in 1st and 2nd gear). I stopped bled the system and it was fine for the rest of the trip. The fans rarely kick in - I checked the switches and they both work, however I wonder if there is an air lock in the radiator, or being the highest point and all, if they are immersed in coolant - especially the 87degree switch. I have an override switch which I very rarely use on ugly hills only.

Ideas?

Thanks

Mike

A. Cooper Member posted September 13, 2002 06:00 PM

Sounds like your temp gauge is working just as it should, and just like every diesel (or gas, for that matter) Vanagon I've ever seen; the needle nearly always hovering just on the righthand edge of the warning LED.

When everything is functioning correctly, your water pump keeps pace with your engine to provide additional flow at higher engine speeds, for fairly steady temperatures. As I said, hills and heavy loads will cause temps to rise, but they should quickly return to normal.

That you smell coolant from the heater core suggests you have a leak there or in a nearby hose. And your expansion tank cap should never leak -- replace that cap. Those two leaks are almost surely where your coolant is going and where your air is coming from. Air in a cooling system can cause cavitation and premature failure of the water pump, and can cause thermoswitches to fail to activate your fan, to say nothing of the reduced overall efficiency of the system.

Small leaks usually only get bigger. A hose failure on the highway is bad enough, but I wouldn't want to blow one out in the boondocks where it sounds like you're going. My wife says I'm the only one stupid enough to take a 20-year old diesel Westy poking around on forest trails, but it sounds like I've found a kindred spirit ....
 

Mike Robinson

New member
I attach a clear plastic hose to the bleed nipple and immerse the other end in a jam jar - to see the air bubbling out.

As advised I rev the engine to 2500rpm and watch the trickle of antifreeze/water coming into the jam jar.

How much pressure should I be getting out of the system - it really is quite a small amount.

This question relates to my concern that I am not sure about the performance of my waterpump, and this should show some indication.

Thanks

Mike
 

tkhaz

New member
87 Westy 2.1, 215,000 total miles, a little over 100,000 on 2nd engine. I replaced the heads and gaskets less than 10,000 miles ago. It runs good and strong, normally.

I recently had a major coolant leak from the water pump seal, had the car towed home, and replaced the water pump and all of the hoses that are in that area. When I refilled the system, I bled it per Bentley and postings on this board. It seemed to run fine with no leaks. Then, on the second in-town trip, it began to “boil” over. The temp guage read about 3/4. The coolant level light began flashing, and coolant began spraying out of the coolant recovery/refill tank (the holes in the top). It was all bubbling furiously and high pressure air filled the expansion tank. When it cooled a bit, I bled the air out of the expansion tank and refilled the tank. The coolant that was in the refill tank was drawn down again when the engine was completely cooled so I think the expansion cap is doing its job.

I need to know whether it could be a bleeding issue- too much air in the system because of incomplete bleeding or some other small leak in the system- or whether that kind of pressure is only caused by something more gruesome like an inner head gasket leak. I don’t have the tools to do a leak down test at home but I can do a standard compression test.

Does a head gasket leak typically show up only after the engine is hot? That’s when this occurs. When I refilled the system again, it fills normally (and the engine runs smoothly) until it starts to get warm. By the time the coolant is flowing at the radiator bleed screw, I get a sort of surge back into the expansion tank and it begins the rapid bubbling after I put on the expansion cap and it’s warm.

Of course, I’d love for this to be bleeding-related and not a head gasket. If I had the heads replaced less than a year ago, does that mean there’s something else wrong with the head/cylinder mating that I should be worried about. I could pretty easily change the gaskets again on whatever side has a leak but I don’t want to throw the time/money away if there’s a more basic problem with the block or something. I’m trying to decide whether the mileage on the engine suggests a new engine rather than another head gasket.

Any insights would be appreciated.
 

tkhaz

New member
I shoulda known! A combination of living at altitude (around 6000') and a sticky thermostat was the source of my problems. My bubbling was indeed boiling over, not air being introduced by some other source, like head gaskets. Leave it to me to project out the worst case scenario. (And I would have hated to admit that I messed up the heads myself somehow. ;-()

Before I broke down and hauled the thing into the dealer to do the pressure tests, I decided to look at the thermostat again. It was a stock 87C thermostat, which means it doesn't open until past 185 degrees F. At my house, water starts to boil at around 180 and gets really rolling at 190. The thermostat was sticky and wouldn't open consistently, mostly it stays shut until well past my boiling point. Easy enough to discover if you try.

I decided to put in an 80C thermostat to see how it works. I do my hardest driving up in the mountains where I'm often up above 8000 feet and always going over some 10,000 foot plus passes. I know the boiling point is very low up there so I figured I'll try the lower temp thermostat to see how it works. The real question will be how it works in winter up high. Will I still get heat??

In any case. Thanks for reading. Hope my mistake helps someone else.
 

Capt. Mike

Moderator
For the most part, thermostats have NO effect on the operating temperatures. Once open, ALL thermostats have the same coolant flow. Your only difference will be in how quickly and far the coolant warms in the block before opening. Since the Westy is designed to operate above 187°F, it just means you will start to get coolant flow a little quicker and thus slow down warmup. The plus is you will get heat quicker with the lower thermostat since the heater cores get their flow from the coolant going to the radiator, which won't start until the thermostat starts to open.

High altitude means boil occurs at lower temperatures. This will be controlled more by your radiator (actually expansion tank) cap relief setting than the thermostat.
 
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D-shima

New member
90 vanagon westy- less than 10k on a reman

Managed to cap a nasty leak related to the senor o-ring. BUT before that was done i did have a consistent drip of about to days before repair (SOGGY cardboard!).

the westy was parked on a slight incline with the driver side up. so i assume the radiator was getting depleted of coolant. i added to the overflow to compensate the loss of fluid but the level did not change much at all.

how do i check the coolant level in my radiator?

i did notice the fan come on randomly around town as i stopped at traffic lights and the jack in the crack drive through( is this normal?). no dramatic change on the temp gauge inside.

Could low coolant level in the radiator cause the fans to come on?

thanks in advance,

d-shima
 

D-shima

New member
ok- being sooooo used to adding coolant up front to my chevy s-10 my brain had a hard time comprehending that on a westy you cannot take the cap off the radiator itself and just pour coolant in. so the answer to my question is no- to add coolant to the radiator, it must be done by adding to the tank in the rear under the hatch.

as for the random fan turning on and off when in town driving - i assume this is normal behavior for the westy- i drove this past weekend (valentines) over 700 miles about 600 on the hiway and i did not have one problem with over heating ( temp gauge right on the middle). the beast performed well!, even climbing to an elevation over 6000 ft in the sequoia national forrest with the temp gauge a notch above the red light.

simple question simple answer to a hard head and a new vehicle

d-shima
 

Stevekdx

New member
Hello,

I'm having difficulty bleeding the system on my 85 1.9L. The problem is that coolant never comes out the bleeder on the top of the radiator. If I leave the expansion cap off, the coolant backs up and runs out. If I put the cap on, nothing happens. The temp gauge is going over about 3/4 (it's never been that far before). I've got the front end raised, and followed all the procedures in the Bentley manual and from this forum. Could my thermostat be stuck or something? It seems unlikely; I drove the van about 150 miles yesterday and the guage never got past halfway.

I replaced the water pump a couple of weeks ago; refilled the lost coolant and everything has worked fine. I signed up for this forum and saw all the posts about bleeding the system so I figured that was something I should do (forgive me I'm a new Westy owner)

One other pertinent piece of info - I could not get the drain plug out of the left side of the engine. So, I only drained one side. Since you don't get all the coolant out anyway, my plan was to flush/bleed several times this summer which would eventually get all the coolant changed.

Any help is appreciated -
Steve
 

Capt. Mike

Moderator
Actually, I've had better luck bleeding the radiator end with the rear jacked up and the front lower. Look at the level of the radiator bleed vs. the bleed at the thermostat. You want the coolant to fill the radiator so having the coolant level higher than the radiator bleed will force fill it.

Don't get to obsessive about the radiator bleed not gushing coolant -- being remote from the expansion tank, it will have a little fluctuation that doesn't really hurt anything if there is no overheating.

A frozen drain plug belongs in the crankcase topic. But you are right in that the amount left in the one cylinder bank is not going to prevent a complete change per the tips posted here and elsewhere on the site. (See "Clearing the Muddy Waters" post in the TIPS forum.)
 

Stevekdx

New member
Thanks for the reply. After I posted my question, I went back to the garage with renewed determination. I finally got the stuck drain out and went through the whole drain/fill process again (both cylinders this time).
Still, no fluid coming out and the radiator was cool even though the temp gauge was at 3/4. I replaced the bleeder, drove it around the block. I released the bleeder and and it spit and sputtered from a while, then fluid ran out, no bubbles. Most of the expansion tank drained, and the radiator warmed up. I went through the bleed process several more times just to make sure.
The gauge doesn't get past the midpoint, and everything is back to normal again. Whew!

I'm not sure, but I think the problem was that I completely removed the bleeder screw from the radiator when I started the bleeding process. Either there was not enough pressure, or an airlock was created. After I replaced it, ran the engine, then cracked it open the airlock was released.

Thanks,
Steve
 

westfaliarage

New member
Hello,

I purchased a 1987 westy last fall. I noticed then that the coolant look like there was no water just antifreeze in the system. I tested it and the needle pegged out at or above -50++ freezing point. I didn't worry about it all winter and now it is warm and spring again I am able to work on it without freezing my digits off.

OK here is what I did. I tried to get to the drain plugs in on engine but bolts holding shield and muffler on looked rusted and unmovable. So I popped of the radiator hose with back end jacked up and drained and got a little better then half the coolant out. I put distilled water back in. I am know at -27 which is a little low for Edmonton Alberta, Canada. The overflow tank needed some so I added some straight "VW" antifreeze.

So here is my possible problem arose!?! I noticed that the "VW" antifreeze I was putting in is blue colored and what was already in the system is green colored. Does this mean that someone (previous owner?) put in the wrong stuff in or does it also come in green???

One other thing there seems to be a moderate amount of flackey white stuff in the overflow tank so is this a problem should I flush. I understand if I have wrong anti-freeze in system I do need to flush!

Thanks in advance for all the help, David
 

Capt. Mike

Moderator
See the "Clearing the muddy waters . . ." topic on coolants in the TIPS forum. This is not a bleeding problem for this topic.

There are also some excellent tips on frozen nuts & bolts in the exhaust system elsewhere on the site -- I forget exactly where right now. I think one is in the TOOLS forum under 'lock nuts'. Others probably in ENGINE under the "Exhaust" topic. Use the search engine.

The white flakey stuff could be just residue from coolant going empty but could be from system corrosion by using a "phosphate" containing anti-freeze. Thus a full flush is in order.

The blue or green color is just dye and indicates it's the conventional technology, which is fine -- just different marketing of the same product.
 

deniseydowling

New member
In my 86 Vanagon Westy GL 2.1 automatic, My coolant level light started blinking after I had a hose replaced. Turns out the expansion tank was only half full(though the refill tank was at the max mark)-- so i'm assuming the machanic "just forgot" to bleed the air out and refill? So I filled the expansion tank and bled as directed(with jacking rear etc). The coolant level sensor is no longer blinking. Though I think I bled the air the best I could through radiator and engine bleed, a small ring of air remains at the very top of the expansion tank that molds around the sensor-- like an air donut around the sensor with the middle part dark with coolant (WITHIN THE TANK) where tank dips in the middle to hold sensor. I have filled the tank to the neck before and after bleeding. Is this remaining bit of air at top of tank normal? --DEMD
 

Capt. Mike

Moderator
No; it indicates you are 'overflowing' during hot coolant to the recovery tank but not redrawing as the coolant cools. It could also indicate air leak such that it doesn't create the vacuum to redraw coolant. Defective expansion tank pressure cap most likely, not bleeding.
 

deniseydowling

New member
Thanks Capt. Mike. (RE: 86 Vanagon GL Automatic)I just replaced the expansion tank pressure cap and I still have that pocket of air at the top ofthe tank. Again, my expansion tank is shaped so that that sensor is not at the very top of the tank but in a dipped well, so plastic rises above the sensor where this air pocket continues even when I fill it up to the neck. The coolant does go into the overflow tank a bit and then receeds back at cool down. I have bled the air out of radiator etc, but that bit of air remains in the exp. tank. The temperature guage seems to stay between a little above the Led sensor light and a notch or two above that in city driving. Is that normal or too warm? The light has not gone on, though it has been tested and works for low coolant and for overheating. not sure if this air bubble thing is related to the temp gauge. And yes, the fan does go work at low and high. I've also checked repeatedly for any leaks of coolant and can;t find or smell any, besides despite the air bubble, the coolant level remains the same in the expansion tank, and between the max and min mark in the overflow tank. Suggestions about this air bubble in expansion tank, and if temp gauge is too high? --Denise
 

Capt. Mike

Moderator
The warning light serves more than one function. The expansion tank has sensors that detect low level -- as long as they are submerged, small air pockets at the top are OK. That is not the only source of signal to the LED.

If the system is working such that it is expanding when hot into the tank, overflowing to the make-up, and then refilling from make-up when cooling down, this is not a bleeding problem. See the other topics for the causes that trigger your symptoms. Your operator's manual will tell you that the position of the gauge without a warning light is not particularly important. Sitting a small amount above the central LED on GL style gauges is normal and as long as the fans kick in as described in their topic, bleeding pockets are not likely.
 

ben

New member
If am right! that light (some years) as another fonction, overheat! ( blinking above 3/4 temp), lately, i have seen strange behavior with the "coolant lignt system", and the problem is NOT related to a faulty coolant system...

By the way.... hello to all
Ben
http://www.benplace.com/
 

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