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Tue Jan 04, 2011 10:17 am

I've got a stumper that I hope you guys can help me with. I've got an 86 Westy that is getting hot during normal driving. The temp gauge climbs quickly and within 20 minutes of around town driving the warning light starts to flash. This is all in below freezing ambient temperature. During all of this the coolant fan never comes on and I can't get any heat from the heaters. My first thought was very low coolant so I checked the level in the radiator by cracking the bleed screw at the top of the radiator, no air, so I know the fan switch in the radiator has water on it. Also I found that the fan will come on if I let the van sit and idle for ten minutes. This makes me think the t'stat is stuck and the radiator never gets warm enough to trigger the fan when there is water flowing over it.

So, if my t'stat is stuck closed wouldn't I still get heat from the heaters? Any ideas?

Tue Jan 04, 2011 10:28 am

First thing I would check is whether the gauge is correct. With IR themometers so cheap at Harbor Freight and such it is pretty easy to see what the temp really is in the vicinity of the sender.

Tue Jan 04, 2011 11:04 am

I assume that your pressure tank is completely full and the overflow tank is full to the mark as well?

If your water pump is working normally, when you remove the cap from the pressure tank and rev the engine you should see the water level draw down and lots of fluid moving in the tank.

You could have multiple problems instead of just one: a clogged radiator, plus bad controls or a bad valve on the front heater and the rear heater valve turned wrong.

Tue Jan 04, 2011 11:13 am

you probably have a bad thermostat i had a similar problem with the temp gauge and it turned out to be the thermostat. the flange on the bottom of the thermostat was bent. had to replace. i didnt get any heat at the heaters and the temp gauge was going above the red light.

Tue Jan 04, 2011 11:41 am

Good call on the gauge accuracy. There is no reason to assume a 22 year old thermistor is still accurate.

Yes, the high and low pressure tanks are completely full. I'll look for the water level and movement with the engine running and the cap off.

How would I know if the radiator is plugged?

Tue Jan 04, 2011 12:19 pm

make sure you have the correct antifreeze/water mixture; 50/50

Tue Jan 04, 2011 12:45 pm

vwjoel wrote: How would I know if the radiator is plugged?

With the engine running, open the radiator. If nothing exciting happens, you might want to do a flush.....

Tue Jan 04, 2011 1:18 pm

vwjoel wrote: ...How would I know if the radiator is plugged?

There's probably a more scientific/elegant way -- but I think I would just crawl under the front with the engine warm-hot & running and feel the inlet and outlet hose below the rad. The outlet should feel less hot but not a lot less.

Tue Jan 04, 2011 1:42 pm

Ahwahnee wrote: There's probably a more scientific/elegant way --

Yeah, but I think my way is more fun......

Tue Jan 04, 2011 1:46 pm

Ahwahnee wrote: vwjoel wrote: ...How would I know if the radiator is plugged?

There's probably a more scientific/elegant way -- but I think I would just crawl under the front with the engine warm-hot & running and feel the inlet and outlet hose below the rad. The outlet should feel less hot but not a lot less.

Actually on a cool day when the thermostat is just barely letting coolant through there may be a major difference in inlet and outlet temps. If you blocked the air flow through the radiator off and still had a cold return once the thermostat opened then you would know little or no coolant was flowing through the radiator.

Tue Jan 04, 2011 1:56 pm

when it was up to temp I loosened the bleed screw on the radiator. It was very exciting. It squirted out around the bolt. There was water and pressure in there.

If the inlet and outlet are cool on the radiator how would I know if it is a t'stat or a bloked radiator? Since it is a side tank design radiator there could be pressure at the bleed port even if the horizontal tubes of the rad are blocked.

Tue Jan 04, 2011 2:00 pm

The thermostat is cheap and easy to replace so you might start there. I would guess that the radiator may be a goner though.

Sat Jan 15, 2011 12:29 pm

So I got my new BEHR radiator in and I'm puting it in. The Bently says to pull the splash shields under the engine and drain the coolant from the heads but they are held on my the lower exhast studs and I would rather not disturb them in case they break off. Instead I lostened the hoses up front from the radiator to the plastic coolant lines. I had my 5 gallon catch pan ready hoping it would catch most of the gush off coolant. But! After removing both radiator hoses from both plastic coolant lines I got about a quart of coolant total! Is this normal?

The facts are these:
- Engine was cold,
- front of the van jacked up aprox 10 degrees.
- The last time I had it up to temp I loostened the bleed screw on the top of the radiator and coolant came out nicely
- The high pressure tank was full prior to removing the rad hoses

Is it normal to get no coolant from the radiator upun removal or should coolant be in there all the time? Could I have another problem other than the radiator?

Sat Jan 15, 2011 1:20 pm

Sounds close to normal to me especially with the front end jacked up. I would have expected more like two quarts as the radiator itself drained down. I would just put the new radiator in and if everything work well then forget about how much or how little drained out.

Sat Jan 15, 2011 4:42 pm

Well three gallons went back in just now after following the Bentley bleading process.. Maybe my problem was low coolant all along. I went for a test drive and it was fine until i climbed a Hill. Now I'm waiting for it to cool down so i can get it home. It is hard typing on this phone. The hose into the radiator is cooking hot and the hose back is cold. The water in the reservoir lowered as i reved the Engine so the pump is working. The t stat checked out in the hot water on the stove test. Something else is restricting flow.

Sat Jan 15, 2011 4:55 pm

I'm surprised only 3 gallons took to fill it. The one thing I learned well is that Vanagons need to have altered speeds. i.e. not an absolutely steady high speed. I slow down 5 to 10 kph and I see a great drop on my separate temp gauge.

When I put my new radiator in, I will be bleeding the entire system, flushing it at least once and then a complete refill using a Libby Bong. I had extreme high temps. I may also change the thermostat at the same time. Hopefully then my boiling will settle down!!! Good luck.

Again surprised only 1 quart came out and 3 gallons in! Don't forget when bleeding the system you have to have the heaters on both front and rear.

Sat Jan 15, 2011 5:02 pm

Your signature shows a Vanaru conversion, just to make sure are we talking about a stock WBXer or some kind of conversion

Sat Jan 15, 2011 5:15 pm

Thanks for the idea daizee. Maybe more will go back in. I didn't drain the engine though just the Rad and t stat.

Yeah this is a stock 86. My flat 6 Subaru never runs this hot even climbing the grapevine in August and it has an identical radiator.

Sat Jan 15, 2011 5:34 pm

There are some incorrect thermostats out there that give problems. I have no experience with them though. I have never heard of a blocked large diameter hose on the cooling system. Sorry I can't offer up any additional help. :cry:

Sat Jan 15, 2011 6:41 pm

I would recommend removing the tstat and test driving it. This will be a good check to see if it is a restriction or a faulty tstat. Do yourself a favor and make a Libby Bong. It will make your life a lot easier. ](*,) Screw that jacking the front up. Just my opinion. I am curious to see what you are going to find. Good Luck, Joe.