Coolant Leak


Grant

New member
I loose the entire volume of coolant from my resevoir each week. Last time I refilled it I ran the engine for 20 minutes or so and noticed that I lost coolant out of the drainage holes on the driver's side panel. I assume that I must have a nick in one of the long lines to the radiator but is there possibly a more sinister cause?
thanks.
 

Capt. Mike

Moderator
The Vanagon holds about 18 quarts, so theoretically should have a reasonable amount of coolant to make a short trip under easy conditions. It usually takes 3-5 miles just to get warm enough to open the thermostat. The questions quickly becomes how bad a leak, what's it spraying on to, and from where?

If it's spraying into other mechanical equipment or electrical equipment, by all means have it towed. If it's a light spray from somewhere along the undercarriage, and you start with a cold vehicle, you can get a suprising number of miles before it reaches an overheat point. And, it's always possible to carry some extra water to top off during the trip if it's not on a route where a stop would be dangerous. Do understand your warning light will come on from low tank before you reach an overheat stage -- watch the gauge.

However if it's literally dumping coolant as fast as you can fill it, stick with the safe tow.

I hesitate to recommend a band-aid. Do NOT use one of the stop-leak products. A visible leak or cut might be slowed down with the venerable duct tape, but if you've got to go get parts for a temporary splice, you've reached the point you might as well just take it in to get fixed.
 

Tim Hannink

New member
One area to look for coolant leaks is at the thermostat housing. I found on my '87 camper that the coolant would drip directly on to the exhaust system and vaporize. It would only leak when the engine was hot, so I never had any signs of a leak on my garage floor.
I recently replaced all of the cooling system hoses in the engine compartment and found that the thermostat housing had deteriorated where it attaches to the left cylinder head, allowing coolant to squeeze by the o-ring.
I haven't had to add any coolant since, where before I used to add it every other week.

Tim Hannink
Goldibox - 1987 Westfalia Camper, Wolfsburg Edition
Winter Park, Florida http://home.earthlink.net/~tjhannink/
 

Grant

New member
As is expected, Capt. Mike is correct again. My heater core (which was supposed to have been replaced by the prior owner) had a broken pressure screw, the little white plastic one. It was causing a coolant leak under the housing box which would run with gravity depending on where my van was parked. Thus it seemed that I had a cracked hose or some other leak. At least I don't feel too ridiculous, my mechanic didn't think of the heater core as the source of the leak either. Must be a touch of that head gasket paranoia that made us over look the obvious probability!
 

turg

New member
I have a 1991 GL Westy. When the coolant temperature gets to the engine operating temperature, the coolant leaks at the level sensor. I've change the sensor. I still have the problem. It leaks till the level gets halfway in the expansion tank. The leak stops but the warning light is blinking all the time since le coolant level is too low. The temperature of the engine remains in the normal zone. Do I have to change the expansion tank ?
Best regards.

[ 08-02-2001: Message edited by: Gilles H Turmel ]
 

Capt. Mike

Moderator
The sensor is part of the pressurized expansion tank, thus would be subject to the same 13-17 psi of the system until released by the pressure cap. It has the O-ring to seal and withstand those pressures. Check the cap to be sure it's releasing at the correct pressure (Bentley 19.18), and if so, you'll have to determine if it's improper sealing at the O-ring or a damaged seat. The O-ring is replaceable -- should have been done automatically with the new sender -- but seat damage will probably require a new tank.

Look for stress cracks around the neck -- this is becoming common on older tanks.
 

dpender

New member
I have a slow drip coolant leak ('87 Westy). It drips off the left cylinder head at the head cover. My first thought was head gasket, but I can't find evidence of a leak there. Next thought was a cracked cylinder head. It seems the cooling is collecting on top of the head, then running down to the bottom. It happens to be close to what I think is the thermostat housing. I read TJ Hannink's message of 7-31-2001, which sounds similar to my situation. I plan to check this first before going so far as considering replacement of the head.

Any thoughts?
icon_confused.gif
 

dpender

New member
Thanks for the tip on the pressure test. I checked Bentley for the procedure and tester....I got the tester but am having problems finding the adapter. The Stant catalogues are less than explicit about which adapter is required, though I suspect it is the one that is typical for all water cooled VW's.

Is this an exotic part? Do you have a lead for an on line parts house that might have this adapter?

Thanks,
 

Capt. Mike

Moderator
The VW manual shows the tank having a flange type neck and standard cap but most later models had a threaded neck and screw cap. In an off-site email, one member told me they didn't need any specialized adaptor, the standard ones in the tester kit did fine.

Swing by your VW dealer and ask to look at his. Most of them are pretty nice that way if approached right. It's quite possible the same adapter will fit both. Since his is surely a US manufacture, you can at least get the name of the supplier.
 

dpender

New member
Thanks,

I got a Stant Tester and a Stant 12016 adapter the fits the threaded neck on my coolant reservoir.

I pumped the system up to 14.5 psi as recommended by Bentley. A small amount of coolant is coming from the thermostat housing....mostly at the sender unit connection....maybe a little where the housing meets the cylinder head.

A little more disconcerting is fluid running down just below the cylinder head nut located between the spark plug and the thermostat housing. Its a little hard to tell exactly where that is coming from. It does not seem to be coming from the spark plug connection. I suppose its possible its coming from the cylinder head nut. I suppose it is also possible it is migrating the short distance from the thermostat housing. The thing about the head nut is why it would suddenly start leaking there when now work has been done on that side of the engine.

Does this sound logical to you or do you think it sounds like the head nut, or worse, an invisible crack in the head?

I read the thread on reman or rebuild engines....esp. the part dealing with a leak at the nut. Based on that one, the leak is very slow, its a pain to smell the coolant dripping on the exhaust, but maybe this is one to just live with rather than pull the heads to fix the leak at the nut.

Thanks.

[ 01-05-2002: Message edited by: dpender ]
 

Capt. Mike

Moderator
Next time you are draining the coolant for routine change, you can remove the nut, de-grease and recoat with sealant (VW P/N AKD 456 000 01). The studs are in the coolant jacket so the sealant on the nut is what keeps them from leaking. Bentley page 15.21.
 

dpender

New member
How can I be sure there is not a leak into the combustion chamber? The reason I asked is after I did the pressure test the cylinder nearest the leak did not fire. In the morning it did, so I don't really know what is up there.
 

ben

New member
Fist you should see white smoke in the back!

If not, try the following test:
Start the engine cold with no pressure indicated on the gauge. The pressure in the cooling system builds to aprox 7 lbs at normal running temps looking around for leaks. But if the pressure builds quickly to around 15 lbs the pressure is coming from one of the cylinders through the inner head gasket. In extreme cases the cylinder can fill with coolant, and will not turn over. This is know as hydraulic lock, and if you suspect this pull the spark plugs and tries to turn the engine again. Pulling the plugs from the engine allows water to escape from the spark plug holes.

Regards and good luck

[ 01-07-2002: Message edited by: ben ]
 

dpender

New member
Thanks for the guidance.

No white smoke in back! But I'll still do the pressure test while running the engine as you suggest.

If I can fix this leak by tightening the stud, that's great. I thought that might be a problem due to the tightening sequence required when replacing the head. Aparently if the head is already seated this sequence is not required....???

Many thanks to Mike and Ben for the advice.
 

Capt. Mike

Moderator
Fixing the leak by tightening the nut was NOT given in the first solution deliberately. It's rather rare that a nut with sealant 'works loose' after that many miles. The nuts should be torqued to the specified 37 ft-lb. (assumes new washer & fresh sealant) only! Do not attempt to stop the leak by over-tightening; this could pull the stud, requiring major engine repairs.
 

dpender

New member
I pulled the nut, applied sealant and torqued slowly to 37 ft #'s.....also replaced the "O" rings at the thermostat housing. The "O" rings did the trick for those leaks, but there still seems to be a small leak at the nut. One little detail.....you mentioned replacing the sealant AND WASHER. When I pulled the nut there was no washer there and it doesn't appear there is a washer on the other head either at this location. Is there a special washer that goes at this location that could be part of the problem?

If not, I may try to do the procedure one more time and if it doesn't work consider replacing the head.
 

Capt. Mike

Moderator
Apparently there has been a supercession. Diagram 13.36 shows a nut and washer and calls for sealant on the washer. 13.37 appears to have a washer built into the cap nut style shown there. Parts fich calls for a cap nut on an '87 without mentioning a washer. They have a new part number for the sealant, D 000 400.

When replacing heads or other components where the through bolt is subject to a liquid or pressure, it's prudent to replace the washers. This is to prevent a used washer from having some damage or distortion and contributing to a leak. A washer burr could even score or damage the seat. The same is true of a cap bolt where the sealing surface is built in.

In your case, I wonder if the head is damaged or scored at the nut seat and is the nut itself perfectly smooth? You might try a spring washer underneath with the sealant as in 13.36. The spring washer is thin enough it shouldn't reduce nut engagement and they are used as sealing washers in many instances. That might save pulling the head.

Unfortunately, I've heard of more than one instance where the apparently small supporting surface or ear of the head where the stud goes through has been cracked or damaged during installation -- once on a factory reman. We'll hope it's not that.
 

dpender

New member
Thanks again for the thoughts.

After some meditation on the subject, and a second try at sealing the leak, I decided to have the head pulled and replaced. While I'm at it I am replacing o rings, some hoses, even some old fuel hose.

I'm going to be into it for more bread than I had hoped, but I'm looking forward to the joy of a tight machine again!

Now on to what I think may be a bad crank shaft bearing in my '61 beetle!

Onward through the fog!
:cool:
 

Capt. Mike

Moderator
Transferred to consolidate same topic.

coolant leak

Dru Junior Member # 2364 posted 04-20-2002 03:58 PM

I recently spent four months in Chapel Hill, NC, selling my house and then drove my '85 Westy - fully loaded - back to Mexico, a journey of about 2300 miles.

Since returning to Mexico a few weeks ago, I've noticed I sometimes have copious amounts of coolant leakage; other times none at all. I keep newspaper under the back of the van to check for leaks.

My mechanic, who trained in the States, seems to think I have a water pump problem, but I'm not sure because the leaks seem to occur with very short (five miles or so) trips and not longer ones (fifteen miles or so).

Since getting any repair in Mexico is a very time-consuming proposition (three days estimate for a rebuilt water pump), I'd appreciate your advice before I take the plunge.

Thanks so very much.
 

Top