Ok, so i put in a 2 row single sided aluminum radiator, new OEM radiator cap with install, the fan is a pusher fan located at the front of the radiator. The car puts out great heat when im moving/driving, but if im at a light or letting the car warm up it will not put out ANY heat. The oil is NOT milky, the radiator fluid is nice and green no swirls from oil. I also bled the system completely. Still not sure why its doin this, but i need this fixed so in the winter, i can defrost my windsheild and let the car warm up. HELP! thx in advance and sorry bout my other thread.
thermostat must be stuck open not letting it hold heat. You need to check both upper and lower rad hoses to see if they are the same temp or not.
The upper hose should warm up first and if the thermostat is working well then both hoses should be different temps 3-5 min after cold start…
you you dont notice a difference in temp onthe hoses while warming up then its stuck open.
i do notice that if i start it and let it sit there for awhile… the upper hose is full of pressure and hot ass shit, and the lower is cold and full of pressure. My buddy just tried to tell me maybe cuz its getting colder that the radiator is cooling “too good” or whatever.
OK guys lets try round 2… The car will only put out good heat if im driving. But if im letting the car warm up or if im at a stop light i get zero heat! Heres a list of what ive checked out and/or replaced:
New water pump
New T-belt
New thermostat, (mishimoto)
New single sided 2 row radiator
The prop valve works like it should
Now just 5mins ago i let car warm up completely, i went to take the radiator cap off and it let out a tiny little pfft, and that was it. Im gettin down to the nitty gritty here, and my dad is thinkin its air locked, but im not sure. The car doesnt overheat, so that makes me think that the head gasket is ok. A couple gen2 guys have told me to check my passenger floor to see if its wet in case the heater core is bad, but thats dry as a bone. Im really at a loss and not sure where to turn next. Any help would be great, thanks in advance.
Try and back flush the heater core. Natualy the coolant flows into the heater core through the hose with the valve(upper) and out of the lower hose. disconnect both from the motor and find a way to hook a hose up to the lower hose and flush what coolant is left into a bucket. this should clear out any blockage in the core.
Before you do that. try this! take a piece of card board and cover half of the radiator. if you manage to get some heat this way, chances are your thermostat is stuck open. this will prevent the motor from reaching it operating temperture which would make your heater ineffective. Also make sure the heater is going full blast while bleeding too double check that there is no air in the system as that would prevent coolant from flowing and no heat…
if the t-stat were stuck open, engine temp would drop down at cruising speed. if it’s not doing that, i highly doubt it’s the t-stat.
it’s gonna be your heater core, as suggested. it’s probably half filled with crud. you can test by feeling on the heater core supply and return hoses at operating temp. with the heater on blast, they should feel roughly the same temp.
back flush the heater core, as suggested. hopefully you can get most of it out
Just throwing this out there since I had the same problem for a while a few years ago. I know you said you bled the system but here’s what I had to do. I let the car idle with the radiator cap off and the blower temperature turned all the way to max heat and ran the blower (not air conditioning). I’m not sure if my fans ever kicked on or not but I let it idle like this for about 20 mins and revved the engine up to about 2500 and held it for a few seconds several times throughout the idle time. I then bled any leftover air from the little bled screw near the top radiator hose and put the cap back on. That fixed my problem.
more than likely it just needs to be bled from the way it sounds. When I worked at the dealer I had problem cars that didnt like to be bled so sometimes I would jack the front as high as I could get it and then start bleeding it like that. Makes the air want to naturally escape
Thx guys, got a lot of stuff to look at and try out. The temp does drop when im moving, but i figured it was the mishimoto t-stat. Its cold, aluminum rad, 140 degree t-stat.