Coolant Bleeding


New member
since I changed the cap on the expansion tank on my 1986 2.1 vanagon, coolant still dumps into the reserve tank but when it cools, it does not suck the coolant back. The coolant remains above max in the tank behind the licence plate, the the collant in the expansion tank sits about half way. This remains about the same, without any signs of leaking. suggestions?

Capt. Mike

This indicates two probably areas. The first is your system is not air-tight. i.e. when the coolant expands, it flows into the make-up tank, but then can get air elsewhere so that it takes that easier route out when relieving the vacuum created by the cooling fluid. This could be the hose between the tanks, the cap fit itself, or a crack in the tank. Are you sure the fluid overflow is going into the make-up tank? And that it is not just staying at the max mark because it is now out of the loop? Perform a cooling system check per Bentley 19.17-19.18.

The other is the cap itself. Is it a factory OE or OEM? The cap must be matched to the system. It is a pressure relief cap in one mode -- expansion of hot coolant -- and becomes the check-valve to allow coolant from the make-up tank back in as the coolant cools and creates a vacuum.

Neither of these are likely bleeding problems. See the "Coolant leak" and "Coolant recovery bottle" topics.


New member
HI, I have a 1987 manual 2wd Westy and I have never been able to get coolant to flow out of the rear bleeder valve that sits on top just in front of the engine. Could it be blocked?

thanks for the help in advance.

Capt. Mike

I wouldn't worry about it. It's there for "filling" and bleeds the "from radiator" line, which should have little air due to the good bleeding provided at the radiator already. The '87 has the self-bleeding system and once I've bled up front to clear the radiator and most of the lines, I've never got more than a dribble from the one on the thermostat housing either. The minute the thermostat opens first run, it complete clears that line.


New member
89 Vanagon Cooling System After Engine Rebuild

89 Vanagon Westfalia, 2.1L engine, ~ 1,000 miles on rebuild

I am hoping I can get clarification (or confirmation) on coolant system levels in the expansion and refill tanks. From my reading of my Bentley manual, the Vanagon owners manual, and the Coolant Bleeding thread here is what I think I understand about how things operate and should be.

Expansion tank should be full to the top
Refill tank should be between Min and Max marks. This will fluctuate between higher (at operating temp) and lower after engine cool down.

The reason I am looking for clarification is that when I first got my van back after the engine rebuild it ran hot (about ¾ of temp gauge, also smelled hot). I took the van back to the mechanic at ~200 miles and he re-bled the system. The engine then seemed to run closer to what I remember from prior to the rebuild (a little above the indicator light on the gauge). At this point, the fluid in the expansion tank was about the level of the upper hose (goes to the rear coolant system white plastic line) and there was no fluid in the refill tank. I then added about a pint of 50/50 (VW blue coolant/water) and checked after about a 300 mile drive. The refill tank was empty. I then added about ½ pint water (at campground, no coolant available). After I got home I checked and the refill tank was dry again. I then talked with my mechanic and added more 50/50 (~ 1 ½ pints) to bring the level half way between Min and Max. After driving around town yesterday the expansion tank is now total full (engine completely cool after overnight sit) and the refill tank is down to about the hose level at tank bottom. Throughout this whole process the indicator light has never flashed, the cooling system fans seemed to be working fine, and I have no coolant leaks (nearly all hoses were replaced at rebuild and radiator flushed).

I should note that after the coolants additions I have done the temp gauge is now reading at the bottom or middle of indicator light position on the temp gauge.

So my question is this, is it normal to have to add some coolant after the initial fill and bleeding? Can I add more in the re-fill tank at this point (back to the Min mark) or is it possible to overfill system and cause problems?

Thanks in advance for any and all help. Hopefully, I did this post correctly.

Capt. Mike

You are correct -- expansion tank full, feed tank between min & max marks. It's fairly common to have to add a couple of times after a change. The extent you have experienced just indicates poor refill & bleed technique. However, if the initial refill (during which he SHOULD have flushed & emptied the system as a routine precaution) amount was equal to capacity, I'd look for a leak. Engine rebuilds are done due to wear &/or damage that leads to the possibility of contamination of the cooling system as well. Complete flush and replacement of coolant during an overhaul is a wise policy.
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New member

84 Vanagon VW

I am trying to bleed the system but am not sure if I am doing it correctly. The tip that was given must be for a newer vanagon because the thermostat on mine is the lowest on the whole engine. The bleeder valve in the back does not work but Bently says not to worry about it.
Do you have a detailed summary of how to bleed these systems? How high do you raise the front, or back?



New member
hotter than usual

this is sort of a long saga. I don't know where to put it, if it does not belong here, I'm sorry. we left on our trip to northern nm. we knew the linkage needing parts, so we stopped at foreign aide in Albuq. and gave them our list. it started out that we wanted to buy the ball, socket and bushing for the linkage. they had all that and the price was good. on the way up there the van was blasting us out with hot air, even thought DH had turned off the valve above the spare tire. it had smelled like hot coolant, and I thought it might be leaking there. they had that valve too. after looking at the pile of parts, and thinking about driving up into the mountains, we decided to have the shop put the parts in.

so we waited while they put in the new linkage parts. then the mechanic working on the valve to shut off the heater had some trouble installing it. finally it was ready, and we drove off, only to overheat badly within a few miles of city driving. we went back to the shop, careful to avoid letting the temp gauge go up before stopping and cooling down. they thought the fan wasn't going on, but it had been running fine before they worked on it. so they bled the cooling system. still the fan didn't go on. it was getting near closing on a friday nite, so they installed a toggle switch to manually turn on radiator fan. shop manager said, this is not a good fix. when you get to your mechanic, get to the bottom of this. so we went on, and the van was running around 2/3 up the temp gauge most of the way. a few times it was a little higher, but for the most part, given the time of year, and the climb, we felt it was acceptable. also the blast furnace was turned off, and it was a big improvement as far as our comfort went.

on the way home, it was doing about the same as far as the running temp. we stopped for gas in Los Lunas, and I saw a pool of coolant under the van. my DH put in water, we left the radiator fan running and let her cool down. I did some asking and calling around, and was told there was a very good vw mechanic in the town. so we called and got directions. the needle went to the hot end of the gauge very quickly, and the red light started blinking. pulled over, turned it off and left the fan running. we did this a few times and got to the shop where they found a hose with a hole in it. they fixed it, bled the system again, and we were on our way.

Neither of these shops elevated the front of the van to bleed the radiator.

the van still is not running as cool as it used to run. it is summer, we are using the air, but I still feel it isn't cooling right. So I called a mechanic in El Paso who does a nice job restoring Vanagons. He seems very knowlagable, and I'm hoping we have found our mechanic. I told him I suspected the radiator, he said bleed it with the front elevated first, that nothing else really works. He told me, step by step, how to do it. and offered to take our call while we were going through the steps if we have trouble or questions.

I hope and pray the engine hasn't suffered. I feel that somehow the heater valve has something to do with it. or perhaps air was introduced when they changed it. our van has aftermarket dash air that works really well, but what if something was changed when they installed it?

sorry, this trouble shooting leads to so many questions!