What does this sound like to you?

I had the engine rebuilt 1 1/2 years ago in the summer. At the time I never bothered to check to see if the heater worked. Winter came and heater blew cold air at idle. When I would drive, it would blow hot. The performance shop that rebuilt my motor said I probably had air in my coolant line. I purged accordingly. It temporarily fixed the heater. Summer came and I no longer needed the heater. Winter is back and I'm using my heater now and its still doing the same thing, however, this year is different. PLEASE NOTE: I was stuck at a train stop. I was idling while the heater was blowing cold air and I looked over at the temp gauge and it was close to the "H" spot. Train left and I started driving and the temp gauge went back to normal. I drove the car home and let it cool off over night. I went to purge the air out of the coolant line again. For those that understand how this is done, I won't explain, for those that don't know, oh well. I had the heater running full blast and I heard the fans kick on and all of a sudden the coolant started flowing out the top of the radiator and the temp gauge skyrocketed.

What does everyone think? My thermostat gone? Or a more serious issue?

 

sounds like a T-stat to me...good luck

 

That's the only thing I can think of. I have it in a shop right now. They did a temp test of the coolant on both sides of the radiator. I don't remember their exact words, but they were pretty confident that its the thermostat. Hopefully this takes care of my thermostat and heater issue.

 

Its a no go. They put in a new thermostat and the car is still overheating. I need some ideas everyone.

 

What kind of test did they do?

you said they are pretty confident it's the radiator, are they telling you it's a bad core in the radiator?

Did they test the water pump? a bad impeller on a water pump would cause the high temps but IDK about the heater issues if it is this.

 

I misspoke in that second post. They thought that it was the thermostat, not the radiator.

I just got off the phone with my uncle. Used to be a mechanic back in the day. He thinks that it could be one of two things. Since I'm losing coolant but don't have any visual leaks, he thinks that it could be leaking out of the radiator cap, which doesn't explain the overheating. He also thinks that perhaps it could be a bad water pump, which could (?) explain the overflow out of the top of the radiator. He also said since the heater isn't working, that the water pump could possibly be the reason why.

 

usually if the water pump is on it's way out they will leak out of the "weep hole" that is the warning sign.

 

heater core

 

that explains the lack of heat or the overheating issue?

 

Coolant issues are a PIA but there's always a way to figure them out. Now
you know it's not the thermostat let the engine run with the radiator cap off
and watch the flow....not moving? Radiator core is plugged up, water pumps
leak when they've gone bad. Just had our Vets water pump replaced yesterday, puddles on the garage floor. Oh yea, I always test thermostats
before installing them (pan on the stove) new doesn't mean they work!
Gary

 

losing coolant and no leaks and they just did a rebuild? headgasket... warped heads... etc. may want to get a block test or compression test to see if there's an internal leak. if a coolant pressure test didn't show anything leaking externally likely you're burning the coolant. is it running rough at all? how much coolant are you losing?

 

Absolutely no external leaking that I'm aware of. I'm not seeing any residue anywhere on that engine or on the floor at home. They ran studs instead of the stock bolts for the head so I'd like to thing thats not the problem. Car is not running rough at all. Starts up like stock and runs good. If the motor was injesting the coolant, couldn't it hydrolock? Pretty sure that it was a Nismo (?) head gasket or upgrade. Not sure.

 

Thermostat was replaced. They did a radiator flow test and it was fine. I had the cap off and the fluid started pouring out of the cap (WHILE THE HEATER WAS ON). With the heater off, the car doesn't overheat.

 

Just got final word from them. They got all the air out of the system. Ran a flow test with clear tubing and the flow stopped and air was getting back into the system. They did a coolant pressure test and said that there was no external leaking. They said possibly blown head gasket or worse! NOT THIS **** AGAIN!!!! They said that they have this kit that attaches to the coolant line and that when air passes by it, it'll be drawn up inside of this contraption and inside this contraption, there is a chemical dye that will turn colors if there is carbon dioxide present in the system. If that is the case, then there will be some issues on these boards as this car has been babied since it was rebuilt. I also made sure that these problems were documented since last year.

 

Well, good news. After 4 days there and all these test, it turns out that the air is not contaminated carbon dioxide (monoxide?). They decided to do a vaccuum on the coolant line that pulls all the air out of the system and now the car is running fine and the heater is working. I need one of those vaccuum systems. They said that they are going to keep it over night for some more observations just to make sure that it is safe.


I'm as happy as a clam.


I didn't want to say this, but the reason why I was so concerned about this being my motor is that I'm still paying off my credit cards for this motor and more importantly, we are in the process of adoption which we will be getting our little girl in the middle of December and as everyone know... Adoptions are NOT cheap. Thanks to everyone that chimed in here, whether the suggestions were from the hip or whether they were educated suggestion. Thank you. That is why we need to continue to respond to other peoples cries, because even if it doesn't help with the car, it still makes you feel like people care. See ya around the boards!