Cooling System Issue - 1990

[JDE81]

Hi All,

I just bought a 1990 Vanagon in Oregon & drove it back to Tennessee (2,547 miles!). Trip went well, with the exception of the coolant level light flashing most of the time. I bought some coolant with the intent to top it off, but when I tried to open the overflow tank, coolant would run out, so I never added any. The temp gauge ran in the normal spot around the bottom of the red light, so I chalked it up to a bad coolant level sensor.

After I got home, I started looking around more at the system, and noticed the expansion tank was indeed at a low level, so maybe it wasn't the sensor afterall. I took some coolant out of the overflow tank (got it between the min/max lines) & topped off the expansion tank, started it up, and coolant started seeping out around the sensor. I ordered another sensor and installed it yesterday. All seemed to be fine until the engine started heating up and building pressure. At that point, the level in the expansion tank decreased to a level below the min line and the light starts flashing.

Thinking I had air in the system (I can still see some bubbles in the clear lines), I decided to try to bleed the system per the instructions on here, and the Bentley manual with no luck (I wasn't able to raise the front or rear, so maybe that's why it didn't work). At this point, if I take the blue cap off (I got and installed a new cap too) the pressure releases and the expansion tank fills up. At one point I had the blue cap off and when I opened the bleeder on the front, the coolant overflowed out of the expansion tank.

The level in the overflow tank has never changed (other than me doing it) and there are no visible leaks (no coolant on the floor).

Does it sound like I just need to bleed the system again, or do I perhaps have a worse problem?

Thanks in advance for the help!!

Jason

[Guybrush]

I know some people swear by different methods, raise the van and use gravity, use a pump, use the Libby Bong (I've tried all 3). What's worked best for me, and made even more obvious during my recent conversion, where I thought something was very wrong until I accepted that it's just air, is to simply open the bleeder with engine idling hot, as mentioned in the manuals.

Top off your expansion tank, and the overflow to the line. Close everything.

Start your engine and let it idle until warm. Remove your front grille. Wear gloves and eye protection for safety, but do not put your face near it anyway. Feel the sides of the radiator so you know when it gets hot. If you're worried about spilling, place a little bucked right below.

After several minutes and the van is fully warmed up, open the bleeder screw. You might hear air come out. Wait until coolant dribbles out, then close it. Stop the van and let it cool down. When it's safe, feel around the hose connections with your hands to check for a leak.

When cooled, check the level in the expansion tank and overflow and top off again. Redo the procedure a couple times and see what it looks like.

If the level in your expansion tank stabilizes, do not open it again, keep the pressure in there, and just check the overflow until that one is fine.

If the proper temp and level is maintained at idle, test on a drive (get it hot), then check level again.

Do not open both expansion tank and bleeder screw at the same time as that would let air back into the radiator.

Well, that's what I'd do.

[Tom Powell]

You will get a flashing red light from the expansion tank if:
1. The coolant level is low
or
2. The sensor is dirty or inoperable
or
3. The sensor connections are corroded or broken

You can clean the sensor with bronze wool and vinegar. You can clean the connections or repair broken wiring.

When cold you can top off the expansion cap with coolant. If it is hot you'll get a hot shower when you take the blue cap off. The blue caps go bad and are often BOOB.

Keep the overflow tank at the max line. The system is self bleeding to a limited extent, but enough air in the system can cause a lack of circulation, overheat, and a flashing light. The radiator fan is often a better indication of operating temperature than the gauge.

Aloha
tp

[T3 Pilot]

Simple way to get the job done........ no hot coolant, no expensive tools (a bike pump would work)

Remember to open your heater valves before bleeding.

http://www.thesamba.com/vw/forum/viewtopic.php?t=573302&start=0
_________________
1988 Vanagon

The most important part in every vehicle is the nut behind the wheel......

[JDE81]

I bled the system more today and air in the system seems to have been the issue. I drove it around a bit tonight and didn't get the red light anymore. Thanks for the help!!

[Wildthings]

If you had a problem with leakage around the threads of the level sensor, you probably at a minimum are going to want to get a new o-ring for the sensor. If the sensor and/or tank appear aged, then it would be best to consider replacing both the sensor and the tank as they can and will fail catastrophically. You can buy aluminum expansion tanks from Rocky Mountain Westy and others, this eliminates a host of problems but does make it that much harder to monitor the coolant level in the expansion tank.

[JDE81]

Well, I thought it was fixed, but it looks like I'm still having an issue. First thing I did was replace the level sensor (with a nice new o-ring which sealed up nicely) and I also installed a new Blau cap. Bled the system and all seemed to be fine for a couple of days. Now what I'm seeing is the overflow tank is almost completely full, so it looks to me like it's getting in there with no problem, but can't get back in the expansion tank to keep the lever where it needs to be. Could it possibly be the hose between the expansion tank and overflow tank? Or something worse? I'm still not seeing any leaks.

Thanks.

[Wildthings]

You need a perfect seal on the hose running between the expansion tank and the overflow tank for the system to work.

Also if you have a compression leak it will tend to push coolant from the expansion tank into the overflow tank and it will not return.

[JDE81]

I was afraid that's what I was going to hear. I'm going to try a new hose first and see where that leads me.

Thanks wildthings (and everyone else)!

[JDE81]

Update:

After replacing the cap (2nd time), changing the hose, and adding some stop leak to the system, everything worked fine for awhile. Recently the light started flashing again (low coolant, not temp).

First time: bled off pressure, coolant returned to tank

Second time: noticed coolant has started to go into the overflow, but not returning to expansion tank once cool. I've also noticed that in the pressure cap there is a fiberglass like substance. This also appeared in the Bleu cap that I replaced. I'm thinking perhaps that it's clogged and not allowing the pressure cap to function properly.

I took a pic and showed by dad and uncle (both mechanics) and they said they've never seen anything like that before. Has anyone here ever seen anything like it? I'm thinking I need to flush the coolant and get some new stuff in there. When I drain it from the overflow to put back into the expansion it is a dark green and looks dirty.

I'm pretty much anticipating having a big expensive project ahead of me, but I'd like to buy as much time as I can.

Thanks.

[E1]

Hope I'm wrong... and am a newbie... but it's starting to sound like exhaust gases getting into the coolant. Then again, that's what I thought of mine!

So don't be too hasty, I almost was... then realized part of my issues were even the new, non-German blue caps could be bad. Try sucking and blowing on it to make sure it "bugles." It's also easier than you might think to still have air in the system, I chased it for weeks when first bought and learning the system. I also had a couple leaky hoses and a bad o-ring at the heater under the bench seat.

You might pressure-test as well to check for leaks, but in lieu of that at least get it hot (Edit: up to middling temp and fan running) and check for leaky hoses on pavement while fast-idling. DO NOT overheat it, ever, your fan should come on barely right of straight up and the center of straight up and the first overheat mark is as high as I really want to see.

I'd also wanna know you're not overfilling the overflow tank. I was early on, for me it works best between middle and full but that's to be checked only when hot.

Good Luck!
_________________
‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman

[MarkWard]

[JDE81]

My original thought was exhaust gases getting into the cooling system as well (based upon everything I read on here) hence why I tried using the Stop Leak. I figured if I could buy myself some time before I had to decide what my next move will be. There are no external leaks present either.

I'll try to see if I can find a pic I took awhile back of the fiberglass/hairy looking gunk I found in the pressure cap. Regardless, I think it certainly wouldn't hurt a thing to flush the system. At the very least I'll know the coolant is new.

Thanks!

[AndyBees]

Back in August, I noticed my 89 Vanagon would sound like it was "perking" when I shut it down. The Temp Sensor is new and thus never showed it to be over heating...

Fast forward to three T-stat changes (bad ones from local parts store), I finally got it right.

However, I never had an issue with air in the system. Seems it purges itself quite well. I did use a "home-made" vacuum system to pull coolant out when I changed the T-stats... about 1.5 gallons which all went back.

(Note: among all of this, I too, had to clean the coolant level sensor prongs.)

If the heater works fairly well, that would indicate coolant is circulating. After fully warmed-up, while idling, the fan out front should cycle after a few minutes. If it does, that's another indication that coolant is circulating okay.

So, I'm thinking you may have a combo of issues.
_________________
'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[JDE81]

I flushed the cooling system (didn't have much luck with the shop vac method ). Got some new coolant in the system (no more stop leak) and the original problem is back...pushing coolant into the overflow and not refilling the expansion when cooled down. I got a combustion leak tester and it looks like it is indeed exhaust gases.

The engine has 160,000 miles on it. Now I guess I get to decide if I'm going to just repair it or rebuild it. I'd like to do a TDI swap, but I don't think I'm quite ready for that undertaking just yet, although that is the ultimate goal.

Thanks everyone for the advice and information!

[vwwestyman]

I wonder if that fiber stuff is from your stop leak, or a POs attempt at stop leak?
_________________
Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[Terry Kay]

That debris sure looks like shredded fiberglass matting to me.

Never seen any stop leak that profound.
_________________
T.K.

[JDE81]

[E1]

Was it at least fresh oil and a new filter before your trip? If it still runs the same, you probably didn't hurt it.

I always check the dirty oil when you drain it just to make sure there's no metallic artifacts in the oil.
_________________
‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman

[JDE81]