Sudden overheating, missing coolant

[fish0281]

Topped it off with coolant this am. The engine was cold so I could only really fill the radiator, but it only took about a quarter gallon.

The water pump is a distinct possibility since it's due to be replaced. If it is an external leak, it must be a really really slow one, cause there is zero indication of one. I have had Colorado dust all over my truck most of the summer and a coolant leak would show up well on that stuff.

 

[LittleCaesar]

For underneath leaks I always put down some cardboard, then take a look the next day.

If you do have rear heat, I'd start there, then move to the water pump.

 

[fish0281]

It's been a while because I've been away on travel and snowboard season is in full swing, so I've been neglecting the truck lately.

I changed her oil today and while it was draining, I hooked up a pressure tester to the coolant system... in about 5 minutes, the pressure drops from 15psi to almost 10. I think I'll try getting the coolant tested fir exhaust products next, but I am pretty confident it's not a leak and is in fact a small head gasket leak.

 

[TheDurk]

It's been a while because I've been away on travel and snowboard season is in full swing, so I've been neglecting the truck lately.

I changed her oil today and while it was draining, I hooked up a pressure tester to the coolant system... in about 5 minutes, the pressure drops from 15psi to almost 10. I think I'll try getting the coolant tested fir exhaust products next, but I am pretty confident it's not a leak and is in fact a small head gasket leak.

Take a look at your plugs. One of them may be getting steam-washed super clean>>>dead giveaway.

 

[mizzle415]

I had a Mazda pickup several years back. It started overheating and when I'd turn the motor off, I would hear bubbling and gurgling from the motor.

My mechanic buddy had me start the motor when cold (first thing in the AM), with hood open and radiator cap off. Upon start he sniffed the open radiator. Smelled gas and diagnosed my leaking head gasket.

Might give that a try for another data point.

 

[nissanh]

This is how I check exhaust gas going into the coolant system (bad head gasket).

DO it when the engine is COLD.

Open the radiator cap, start the engine, lift the reserve tank cap such that the end of the hose is still under coolant. place your palm on top of the radiator fill port and check for bubbles coming out of the hose in the coolant reserve tank. Few bubbles are OK, but continuous flow of bubbles indicate bad head gasket.

 

[hambob]

Possible interior heater core leak? Also I would check the rear heater lines. I had this happen. She was losing coolant and I checked the engine, rad everything under the hood and it turned out that the rear heater lines rusted away. Not the most obvious place to look. I'll pray to the head gasket gods for you.

 

[fish0281]

Possible interior heater core leak? Also I would check the rear heater lines. I had this happen. She was losing coolant and I checked the engine, rad everything under the hood and it turned out that the rear heater lines rusted away. Not the most obvious place to look. I'll pray to the head gasket gods for you.

My heater lines are completely devoid of rust, as is my entire under carriage... it's an Oregon truck and they don't use salt there.

 

[LittleCaesar]

How does your radiator cap look btw? Is it keeping pressure?

A compression test may be in the future for ya.

 

[fish0281]

Radiator cap looks good and seems to hold pressure for the most part - but I know there is a leak in the system regardless, so I'm not too worried about that right now.

Yeah, I think a compression test &/or a block test is next up.

The bubble test was inconclusive... but I didn't really try very hard either.

 

[Shibby!]

Have you seen it leaking?

My block heater is leaking... its on my to-do list. Has been for a year. Recently it's starting to amount to where I need to top it off a bit.

Interested to see what you find. Was the coolant at proper mix for freezing temps? (generally, 50/50)

 

[fish0281]

Have you seen it leaking?

My block heater is leaking... its on my to-do list. Has been for a year. Recently it's starting to amount to where I need to top it off a bit.

Interested to see what you find. Was the coolant at proper mix for freezing temps? (generally, 50/50)

No signs of leaking anywhere. The mix was close enough haha.

 

[Brian757]

For what its worth, I was having similar problems, with disappearing coolant, and nothing to show for it. I would fill up my reservoir multiple times within a few months. It was a slow disappearance. It however got progressively worse until I found it one day.

I also got my cooling system pressure tested a few times, only to come back with full pressure readings. I saw a small amount of coolant running down the radiator a couple weeks later, and just replaced the radiator, changed upper and lower hoses, fittings, and added an external trans cooler. It was overkill but I just redid the system. Now my reservoir stays full of coolant. Haven't smelled burning coolant since. Truck runs like a top.

 

[newoldwave]

Happened to me too, It turned out to be the radiator cooling fan clutch not kicking in to cool the engine. Replaced at shop, Ok now.

 

[Robb235]

Happened to me too, It turned out to be the radiator cooling fan clutch not kicking in to cool the engine. Replaced at shop, Ok now.

I don't think a failing fan clutch would cause coolant to disappear?

 

[TheDurk]

I don't think a failing fan clutch would cause coolant to disappear?

If it's a 90° day and you are stopped in traffic, you will quickly boil over and lose tons of coolant. Ask me how I know...

 

[fish0281]

I finally got around to replacing the radiator... turns out the top tank was leaking at the corners where it is bonded to the cooling fins. There was a lot of pink build-up along both ends of the top tank. I think all is good now!