Heater not working

Barely a trace in the radiator cap.

 

When looking into the radiator you don’t see any fluid?
That’s not good.

I‘m hoping the best for you buddy, but this isn’t looking good for you.

 

Checked the oil cap and dipstick. Both are clean with no smell. Started the truck and no white smoke from the tail pipe. Radiator took approximately 0.5L to fill. Thinking my next steps will be a compression test for the gasket and a pressure test for the coolant system. Any thoughts?

 

Did I miss anyone mentioning a sticky or stuck thermostat. Cooling systems are quite simple with very few parts. Thermostats are probably the most common cause.

 

Sounds reasonable. Spark plug color may already indicate a head gasket failure. They should be tan at the base of the electrode, if they look all clean they’ve been steam cleaned by coolant.

 

Thermostats, if they get stuck, usually get stuck open not closed. The other way round would lead to overheating right quick

 

Hi guys. Thought I would give a quick update. Took the truck to my mechanic and they suspect the water pump has a slow leak. They didn't have time to take it apart, so I'll have to decide my next move. Thanks for all the advice.

 

That would be very obvious if the WP is leaking. Lots of pink crusty stuff around the shaft?

 

If it were my truck, I would do a test for head gasket leak before spending money on a water pump. There are multiple ways to test for head gasket leak. A compression test isn’t 1 of them.

 

Soooo? After topping off the coolant, did you have good heat?

 

Nothing obvious for leaks. This is the second time I had it checked for leaks by a mechanic. Good pressure both times. Plus I have gone over the truck numerous times myself. Heater actually started working before I topped off the coolant. I don't see any of the obvious signs of a blown head gasket. Had a blown gasket in my Jeep Wrangler years ago and it was very obvious. White smoke, coolant smell, lack of power, milky oil, sludge under oil cap. But I'm not seeing any of those signs. Any other ideas are certainly welcome.

 

Do a pressure test on the cooling system and a leak down test on the cylinders. Wouldn't hurt to check for combustion gas in the cooling system either. Agree, that amount of coolant leaking from anywhere should be fairly obvious.

 

Thanks for the ideas. Pressure test was good on the cooling system. I'll look into the other test. Anyone have an idea when the head gaskets usually go? Truck is a 4cyl with 134k miles.

 

OOOOOOOHHH, 4 cylinder. Then a look at the plastic coolant bypass tube under the intake manifold would be worthwhile.

 

Op, you might have gotten lucky.
Us 6cyl. guys were sweating. Lol


Have you crawled under the truck and looked for any leaks?

 

I'll check the plastic coolant bypass tube tomorrow, thanks. I've crawled under my truck many times to try and find the leak, but had no luck.

 

If it is that bypass pipe, there is a replacement that is metal and requires a different gasket. The pipe is behind the intake manifold.

 

Hi guys. Just thought I would give an update. I have a copy of the description from the mechanic. They believe the water pump has a very slow leak. The coolant system must have got low over time. When I filled up the reservoir, the system took almost all of it immediately. This explains why I lost the entire reservoir in one day, but couldn't find any obvious leaks. I will continue to monitor the coolant and get the water pump looked at as soon as possible. Thanks everyone for the help.

 

I had to replace a water pump on my 1st Gen 2.4L Tacoma - a cousin of the 2.7L. Pump started leaking at 65K. If your water pump is leaking, you should be able to see the leak.