OT - Van Diagostic Time. Again! Overheated


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Trad climber
Topic Author's Original Post - Dec 2, 2012 - 06:54pm PT
So, I had just passed the exits for a town called Shamrock, TX off HWY 40, when I noticed the temp gauge was topping out. I watch my gauges as I drive, and hadn't noticed it running hot until then. I figure it happened quite quickly.

Luckily, I was at a good spot, and juuuust past an exit ramp with a frontage road back about 50 feet. And no traffic. I backed up and off the HWY/Ramp, and turned the van off. But first, I was worried, because I had heard people say to let it idle before turning off, which was not the way I had learned BITD.

Here are the details which may, or may not, provide clues to you Supermen and Taco Belles who might have some suggestions.

I did idle, as I quickly searched the owners manual, which said "Turn it off." Check. The temp did begin to lower with the van idling, but not very much.

I was amazed to find I DID have coolant in the back! I let the van sit for an hour, and was surprised there was just the littlest "tssst" when I did the initial cap turn. Actually - I was surprised that it was as cool to near-touch when I found the coolant after it was sitting maybe 15-20 minutes(I passed my hand over closed cap without touching expecting I would feel heat and there was just a faint heat).

The van cooled, and I checked the level. Down below the cores inside, at least. I put in the coolant I had, which was probably a half jug. It just covered the cores, but not up to the recommended level. Another 3/4 inch or so to be there.

I carefully went to the town, and the temp gauge rose steadily to just below it's usual running temp for the northeast. That worried me, since it had not seemed hot when I added coolant, but - the town was so near that I didn't have time(I am glad) to see if it was going to go further up.

I looked at hoses and don't see anything obvious. No blown rubber. The coolant did seem to have gone out the overflow tube because when I opened the hood initially and looked, the bottom of the tube was wet, and the metal below it too. Not dripping - just had some wetness.

The radiator was not steaming or smoking when I pulled over, nor making any funny noises. It did not creak or groan or anything after turn off either.

So...here I am in Shamrock, population Small. There is a NAPA, but when I asked at the gas station about mechanics, they didn't hop to it with suggestions. The lady was not very helpful, and I have to admit - there were some men customers too, and usually - well, usually people ask questions and at LEAST make SOME kind of suggestion in the line of trying to be helpful. I guess this was just an Off the Bog HWY place with travelers, but the workers weren't all that helpful.

One lady said "Give her So and So's number" which she did, and then she totally blew me off when I began to ask about the surrounding town(direction of downtown and such). There was two clerks, and it wasn't like they were swamped. The lady who helped me had been screwing around looking at someone's jewelry they were selling beforehand and had to be reminded there was a line of people... But NOW she's got people she's got to ring up! Grrr

Anyway - I am going to take it easy tonight, since there's nothing I can do anyway. Hair is being dyed(yay for getting the hair color ahead of time, and I am going to take a luxurious soak in the tub.

Tomorrow I suppose I am going to have to call this Mr/ So and So, since I guess my initial thought - that I had simply gotten a little low on coolant and it was damned hot and full sun, and that I was driving between 65-70 (75MPH speed limit - yikes!) - and that if I fill it back up I'm good to go, is not the best idea since I am going to be like 90 miles from Amarillo once I leave Lucky Shamrock.

So - whaddaya all think?

Trad climber
Save your a_s, reach for the brass...
Dec 2, 2012 - 07:03pm PT
Crimpergirl here on BN's computer

Yer gunna DIE!

Please forgive me. I'm immature and couldn't resist - plus someone had to do it. Hope someone more helpful can step up.
Jim Brennan

Trad climber
Vancouver Canada
Dec 2, 2012 - 07:04pm PT
Over heated but coolant was still cool ?

start with a stuck thermostat.

Good luck and I hope you didn't cook your engine.

Big Wall climber
Terrapin Station
Dec 2, 2012 - 07:07pm PT
I have a 91 GMC van. I also had overheating issues. Especially when I was overloaded or loaded and driving into a headwind.
Turns out I needed a new radiator, and an aftermarket secondary cooling unit. It's a mighty big machine for the cooling system it was built with.

Best of luck!

Trad climber
Dec 2, 2012 - 07:13pm PT
Hope it's just low on coolant and you'll be good to go. Why did it have coolant in the back and you did not know? You should mix coolant with H2O and not use just straight coolant, btw.

Was there any white smoke coming out the tailpipe?
Pull the oil dipstick and check that it's oil on the dipstick and not "mayonnaise".

Either or those might indicate a head gasket problem :(

Hopefully, it's just low coolant/very slow leak. But some possibilities in order of expense/time might be:

Thermostat stuck closed
Bad water pump (could the belt have broken?)
Clogged Radiator
Blown head gasket

Juan Maderita

Trad climber
"OBcean" San Diego, CA
Dec 2, 2012 - 07:22pm PT
Like you said, it could have been low on coolant over time.
There may be a slow leak somewhere and leaking only when hot (pressurized) so you don't notice it until the coolant level is down.

Good chance of a sticky thermostat which fails to open fully.
Install a new thermostat and gasket. It's a cheap part, so just do it. If you take it to a shop, have them pressure test your cooling system. (They pump it up with air and see if the pressure bleeds down).

If doing it yourself, check for coolant leaking at radiator & heater hose connections. Check when it reaches operating temp and then after you shut it off. Look for coolant leaking from the water pump. Look for a telltale weep line of discoloration below the water pump, or a drip. Check that the radiator cap is holding pressure. Look for hardened or torn gasket.

If the new thermostat doesn't have a little hole for air to bleed out, then drill a couple small holes, 1/8" to 3/16". That keeps air pockets out of your engine block when you refill the radiator.

Near Boston
Dec 2, 2012 - 07:32pm PT
Ditto on the sticky thermostat.
Just check the oil too ...just to be sure you head gasket is ok. If there's an issue the oil will be a light tan color.
John M

Dec 2, 2012 - 08:02pm PT
I am not a mechanic, but I have had a radiator cap get weak and slowly lose coolant through the overflow. Some Napas will pressure check the radiator cap for you. Its easy enough.


Trad climber
Topic Author's Reply - Dec 2, 2012 - 08:04pm PT
The coolant was a jug I had bought soon after getting the van. A friend and I had gone over the basics and when we checked the level, it was within the range suggested in the manual, but on the lower side of it. I had forgotten I'd bought it and topped up the level. It was pre-mixed, so not full strength.

I am mad at myself for not checking the coolant level since starting in the trip. I did right before I left and it was fine, and just this MORNING I thought, as I was going to check the oil level "What about the radiator?" But, I had driven the van for a bit and so it was hot. I thought "Well, check it next time you cool out." I am terrified of getting hot spray and so I never would have done it until the next morning. Also, I hadn't stopped for long enough that I would have been comfortable opening it today.

So, I do not know if it was slowly losing fluid.

I haven't checked the oil since this, but will do it in a bit since I just got out of shower. Oil pressure gauge has been reading normal levels and did so after this overheat, but again, I only drove about a total of two miles since.

I didn't notice any smoke, but the van is a big guy and I can't really see his rear end when in the driver's seat. I didn't notice any odors from the tailpipe area when I was back getting the coolant, but don't know if there would be a smell associated with this. Didn't notice any of that "overheated" smell at the front either.

No blown hoses that I could see, and the belt is intact.

I won't be able to replace the thermostat myself. I could probably do it if I had someone coaching me and patiently watching while I took forever to do something easy, but on my own, I just don't feel confident.

I posted to my FB page about it first and Riley came on with some suggestion, similar as what you all are saying. Except he didn't start with Yer Gonna Die!!!

Oh - there's Teddy, up and at the door. He hasn't been feeling good the last two days at all. At all. Long story, but he's not been interested in eating and has very little wish to walk. I did buy some roat chicken and he ate a small amount, and now maybe he will take some more. I'd better go take him out, poor guy.

Russ Walling

Social climber
from Poofters Froth, Wyoming
Dec 2, 2012 - 08:13pm PT
Do you have a multi-meter?

Sport climber
Boulder, Colorado!
Dec 2, 2012 - 08:23pm PT
Happie..check out youtube for changing thermostats. It is generally REALLY easy. Have not done it in decades, but recall it being very simple on my old chevrolet.


Trad climber
Topic Author's Reply - Dec 2, 2012 - 08:31pm PT
Damn, I knew I should have bought that multi-meter...

Will look at the videos but I'm not promising nothing!

I checked the oil and it is normal colored, and expected level. Phew on that one!

Trad climber
Toshi's Station, picking up power converters.
Dec 2, 2012 - 08:40pm PT
no advice but good luck!

feel better Teddy!


Big Wall climber
san jose, ca
Dec 2, 2012 - 08:42pm PT
Just keep driving with the now correct coolant level IMO. If it gets hot stop and head back to the town. It should get hot pretty quickly if something is actually wrong

Trad climber
Nedsterdam CO
Dec 2, 2012 - 08:47pm PT
Get a new radiator cap. Too easy and a very common problem. And swapping out thermostats isn't that hard. As per Crimpie look at youtube.
Best of luck to you!

Trad climber
greater Boss Angeles area
Dec 2, 2012 - 08:51pm PT
I concur with those who suggested thermostadt.

I changed mine earlier this year, and the most expensive part of the job was replacing the coolant. The thermostadt itself was only seven dollars.

You got extra cooant already, so you're in.
John M

Dec 2, 2012 - 08:52pm PT
which vehicle do you have now?

I still say start with radiator cap. Thermostats are easy to change depending on how easy they are to get to.
Juan Maderita

Trad climber
"OBcean" San Diego, CA
Dec 2, 2012 - 09:08pm PT
Sounds like the van has a very small leak somewhere, and you let the coolant level get low. The leak could be as simple as a loose hose clamp. Best time to visually check for leaks is immediately after shutting it down when hot. Or have a shop pressure test the cooling system.

From your description, you don't have a radiator overflow tank/bottle.
(aka: coolant expansion or recovery tank).
At some point, you should install one. The aftermarket part is inexpensive; it's just a translucent plastic tank. I even rigged one on a Subaru powered dune buggy, using a gatorade bottle w/ hole drilled in the cap, and zip ties holding it to the frame. It's on its third season and others are copying the design. The overflow hose from the radiator spills expanded coolant into it as the ehgine heats up. When the engine cools, the extra coolant is sucked back into the radiator. This enable you to visually check the level at a glance, without removing the radiator cap.

You have an old van and don't do the preventative maintenance to keep it reliable. Either you have to get tools and learn how to use them or have your van regularly inspected and maintained if you want to avoid breakdowns on road trips.
No offense intended. Certainly I've had my share of vans and 4x4s with numerous mechanical problems. Hardly a trip goes by that I'm not repairing something, and I'm rather sure it's every Baja trip.

Mountain climber
Anchorage AK, Reno NV
Dec 2, 2012 - 09:18pm PT
Fact you are losing coolant.

Overheating could be due to just low coolant from a very slow leak such as worn out radiator cap. Once coolant gets low enough it may no longer circulate and can remain cool in the radiator while your engine block overheats. Based on the fact that you have low coolant I would not worry at all about the thermostat. Thermostats do not cause leaks.

Personally I would just fill er up and drive on. The one main thing you need to watch for is a heavy white exhaust. If you get that you have a serious problem such as a cracked head.

Otherwise stop from time to time leave the engine running pop the hood and see if you can find the leak. If you don't seee anything turn off the engine and see if you can find the leak. But dont put your hand in there while running... bad stuff can happen lol.

Get back to us once you have filled up and let her run a bit. If you can't find the leak and you don't overheat anymore stop worrying and drive on but keep a couple jugs handy.

The big risk of this advice would be blowing a hose completely out in the middle of nowhere and having to get a ride for a replacement.

Social climber
The internet
Dec 2, 2012 - 09:31pm PT
It's possible the lost coolant is just what blew out the overflow. You do not necessarily have a leak just because it's low. You do want to get under there and look for leaks, though.

Thermostat problems have probably destroyed more engines than all other problems combined. Get that thing replaced. Don't skimp on the new one, either, ie, don't go to AutoZone. A better thermostat will stay open when it fails, has a pressure relief, lasts 100x longer than a piss cheap one, etc. It's like 5-10 extra bucks, no brainer. Thermostats only last 50-100k miles, less in the northland. They are indeed generally easy to replace, but most should keep in mind that nothing is easy to replace in that style of van.

Also consider a cooling system flush with some type of cleaner.

Definitely check the oil. Sell the thing asap if the oil looks milky or if you find too much brown slime in the coolant - either way.

Good luck,

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