Hey all,

So this weekend i took my '90 Pickup 22re 5 speed into the mountains for a little shooting. I was on forest service roads that hadn't been maintained in awhile so we were traveling very slow. Outside temps were in the mid to upper 90's. When we reached the top of the mountain (took us maybe 1.5 hours) i turned the truck off and noticed a gurgling sound under the hood. Popped the hood and saw the coolant boiling in the reservoir. I checked the temp gauge and it read only a quarter way up, not even close to over heating.

I drove the truck home from the eastern part of the state last night, maybe 150 miles and the truck runs fine. No loss of power, no odd smells. Only thing i noticed was that the heater no longer works. When i got home i checked to hear the gurgling sound, and nothing was present. And the truck never over heated on the way home ( i went over 2 passes).

What do you think this could be? Thanks

 

The coolant in the tank wasn't likely "boiling", but rather hot gas was escaping from your radiator past the pressure cap and bubbling up through the liquid in the tank.

Sounds like you're pretty low on coolant in the radiator. When your heater doesn't work and your temp gauge barely moves, it's not a sign that the engine is running cool, but rather a sign that the coolant level is so low that hot liquid is no longer flowing through the heater core or past the temperature sensor. Your engine is baking - you just don't know it.

Wait until the truck cools off (several hours) and then remove your radiator cap and check the coolant level. I'm guessing it's quite low and you won't be able to see any above the radiator cores. Refill it with a 50-50 antifreeze/water mix, and add the appropriate amount to your overflow tank, and see if the heater and temp gauge now work normally. You may or may not have done more damage, but the only way you'll know that is to drive it for a few days or weeks.

You might want to get a new pressure cap, or at least test this one. Also, get in the habit of checking the coolant level in the radiator frequently, not just in the coolant tank.

Oh, and BTW, never take the pressure cap off the radiator when the engine is hot - that's a good way to get scalded.

 

Thanks Ron,

I just went out to the truck on my lunch break and checked the level of coolant in the rad. It was comlpetely filled up to the top (the truck had been sitting for 4 hours). And the reservoir was 1/4 full. Could the issue still be low coolan level or should i move on down the list to the rad cap? Given that information would you suspect anything else?

Thanks again.

 

Could also be a early sign of a blown head gasket. If the radiator is topped off. Try running the engine with the cap removed, if you see a bubble every now and then. It's the head gasket.

 

That's good news that your radiator is still full, but something still doesn't seem right. Let's review your symptoms:
- No heat from the heater
- Low temperature gauge reading
- Apparent boiling in the system after shutdown. (Boiling in any part of the system will force fluid and steam out the overflow, causing bubbling in the overflow tank).

Just the lack of heat and the low gauge reading could be caused by a thermostat stuck open, but that wouldn't explain the apparent boiling after shutdown. Taken all together, it sounds like poor coolant flow, due to a blockage somewhere. Part of the system is hot enough to boil, and the other part is too cold to provide heat or a proper gauge reading. (Your gauge should read about 1/2 way up, not 1/4, when the engine is warmed up.)

Definitely check out the pressure cap, but I'm not too hopeful that's all of it.

 

Get the cap on radiator at highest angle sounds like u had a air pocket but basically need to elevate front as high as possible run engine and let get hot enough with radiator cap off until you see thermostats open(coolant will start to lower) also make sure when your doing this your heaters on full blast otherwise you'll never get air pocket out

 

I'd bet on a blown head gasket.

 

It could also just be the change in pressure from going up the mountain, maybe a cold front went through too... one could hope...

 

I've never heard of that one.

 

Yep, your head gasket is on it's way out. Time to do a pressure test on the cooling system and a compression test. Also a test that shows hydrocarbons in the antifreeze won't hurt either.

Then you will know for sure...

 

As you go up a mountain there is less pressure (extreme, ears pop when you fly). So if you start off in a high pressure area and drive to a low pressure area, say, on top of a mountain, there is more pressure in the tank trying to get out... it is very plausable...

 

That's the stupidest thing I've ever heard.

The cooling system is a closed system, outside pressure has no effect on it. If what your saying is correct, then the radiator cap would need to be variable insted of fixed...

 

X2 Thats what I was thinking

 

Suspect cooling system flow problem.

-Check engine oil... --> if its milky colored then you have internal engine coolant leakage such as a blown head gasket.

Water pump/fan/alternator belt still there and or out of adjustment...?

Thermostat faulty..?

Excessive air in cooling system...?

Water pump faulty...?

Cooling system blockage...?

Debris in cooling system...?

 

Thanks to everyone for the responses. Here is a quick update:

1) Took off rad cap to inspect for oil, saw none. Replaced rad cap with new one.
2)Took off oil cap and inspected oil stick, no evidence of water or coolant in oil. Im assuming id see white gunk.

Replies to the following post are in red.

 

You can observe and feel the water pump externally for physical damage but ideally most water pumps are only able to be thoroughly inspected upon removal.

-Feel hoses. Temperature in various areas of engine.

With engine at normal operating temp are all "radiator" hoses hot to the touch...?

Could not see picture of thermostat... but if your describing "gunk" in the system that could be a red flag.

-Flushing may be a future project...

-"Gunk" or debris in the cooling system usually shows severe trouble for the following items:
-Radiator
-Heater Core
-Thermostat

Possible Radiator flow restriction...?

Thermostat's usually have a pretty long service life. 7K miles is too soon for failure however still very possible.

 

Thanks ill have to inspect the hoses tomorrow after work. Here is a direct link to the busted T-stat.

http://i471.photobucket.com/albums/r...9/photo1-1.jpg
http://i471.photobucket.com/albums/r...989/photo2.jpg
http://i471.photobucket.com/albums/r...989/photo1.jpg

 

x3 lmao

 

id say thats your culprit.. it would be a blockage of the coolant and it wouldnt let the flow thru correctly... make sure to burp the air out after you get it all put back together!

 

I see picture of thermostat now... yea that thermostat is no good ^_^.

Good find.