2005 double-cab Overheating..

I've had an overheating issue for about a year and a half. See if you can guess what it is.
- It overheats on hot days when it's fully loaded and under stress (family + camping gear)
- The coolant comes out the overflow, the temperature gauge starts to fluctuate for a few minutes, I lose heat (out the heater) and then the gauge heads up the the red zone. I'm stopped at this point.
- When temperatures are above 90° it loses about 1 quart of coolant a week.
- During the rest of the year it barely looses any coolant and does okay.

I replaced the radiator cap, thermostat, cleaned the radiator, and looked for leaks. I was sure
(SURE!) it was the head gasket. There is no coolant in the oil, no oil in the coolant, it doesn't belch white smoke nor does the exhaust smell coolant-y, I cannot find a leak anywhere.

As per the shop; There is no exhaust in the coolant, the system holds pressure overnight; and in the morning there is no coolant in the cylinders. There are no obvious drips or leaks.

??

 

Maybe you need to replace the radiator.

 

Lack of heat from the heater core indicates a coolant flow issue, otherwise the heater core would be hot from hot coolant. My guess would be a water pump on its way out.

 

The water pump seemed fine. The estimate to replace the head gasket was between $3,000-4,000! We had to make sure it was the head gasket.. and we weren't sure. So they pulled the radiator and pressure washed it again - and they said there was a ton of debris in there. I had that done a year ago and I haven't had a major truck adventure since. It's been my daily work vehicle only. Then someone suggested the FAN CLUTCH. huh? what's that?
- So we replaced the Fan clutch and the newly cleaned radiator. I loaded the family into it yesterday - it was 93°. We turned up the AC, and climbed 6,000 ft into the Rocky Mountains. I checked the coolant a lot but IT DIDN'T OVERHEAT! Wahoo! I checked it again this morning - all the coolant is there. I believe we solved it. I'm pretty happy.

 

I was going to suggest fan clutch as well, it engages when it gets above a certain temp to engage the fan to cool the radiator, however I don't see how a weak fan clutch would cause the heater core to blow cold.

 

I believe the overflowing coolant just caused the coolant level to drop out of the heater core.

 

Rereading your post, I see the loss of heat was after the overflow, so yes that definitely makes sense. Glad you got it worked out and it is a pretty easy fix too.

 

Only took 21 minutes to guess and replace the fan clutch huh?

 

+1 for you
-1 for the shop.

Good work.

 

Here's an update. My truck overheated again. So far I've changed the thermostat, fan clutch; now the water pump AND radiator. I drove the truck up a mountain canyon in 100degree heat with the AC on and my family in it... and it was okay. It appeared to have lost about 1 pink of coolant. Then I took it on a family camping trip that was 100+ miles away and it overheated when I stopped at a gas station. That means it was slowly losing coolant on the drive and it overheated when we slowed down due to lack of coolant in the system. I'm going to take it in this week to price getting a new head gasket because I think I've run out of ideas. - H

 

I'd say if it's overheated this many times, it needs a head gasket. Maybe have started out as another problem but constant overhearing took its toll

 

I took it in and they did the tests... The gasses in the coolant test, and a a few others... and they all are negative for head gasket problems. They want to do a load test on Friday and I've agreed. I appreciate the need to diagnose before treating but what if all the test are negative? The truck is fine as my daily around town driver but once I load up the family and camping gear, it overheats. Should I put in a new head gasket for $2,700? I can't think of anything else it could be? What about installing an electric fan?

 

Trade that thing. Sounds to me like you're putting bad money in front of bad money.

 

See post #7 in this thread:

https://www.tacomaworld.com/threads/coolant-reservoir-bubbling-and-filling-up.437255/#post-12676768