Trying to figure out why my car runs so hot sometimes...

Its not pushing coolant into the overflow or shooting clouds of steam....but the gauge goes up to the halfway point and sometimes a needle or two past it. It used to stay right on the bottom part of the water symbol on the gauge.

It will usually stay cool when stopped, unless idling for like 15 minutes then it will start to overheat. If I drive above 45mph without the heater/blower on at least one the gauge creeps up to the center. I've noticed it tends to get real hot right when I get off the highway too. And once I've been driving for 2-3 hours it will just start to overheat unless I put the blower on 2-3 with the heater on.

I can find any leaks. I haven't put any coolant in the car in about 3 weeks (since I fixed a leak) and it is still right around full. Recently replaced thermostat 3 weeks ago. All hoses replaced in the last 2-3 months. The radiator was replaced in July. Radiator cap is about 4 months old. I have the stock radiator fan moved to the a/c fans metal shroud on a temp switch, and a secondary fan from a mazda 323 wired to a switch thats always on.

Any one have any ideas what I can do about this? I'm leaning towards the waterpump, but don't those leak out of a weep hole by the bearing once they go bad? Any help is appreciated..

 

It could be your water pump I know when mine went bad it just went into overheat mode and the blades were broke off the pully inside and made a horrible sound.

 

Yeah, I've had waterpumps die on me before and they all made a horrible noise and leaked like hell. I would just pull it to be sure but I'd rather not do a timing belt job right now..

 

Can check to see if there is an air bubble.lots of stuff changed recently,maybe some air in the system.

 

Maybe the fan you have wired to the temp switch isn't coming on when it needs to come on. I would hook them both up to run all the time, and see if that fixes the problem. You would most likely know it if your waterpump failed (crazy noises and/or leaking).

HOWEVER, looking at your sig pic, I think it would be safe to say that your FMIC is definitely stopping some air from getting to your radiator. Is it a bar and plate? They're notorious for not letting a lot of air pass through. Even if it's tube/fin, it may still be the problem. Without replacing it with something that will let more air in, you may want to think about ways to get hot air out of the engine bay, or more powerful fans, or a bigger radiator, or any combination of those things.

One final note...make sure the timing is properly set on your car. If it's too advanced, it can definitely run hot.

 

I was going to go with checking to see when the fans kick on. But maybe you have another faulty thermostat. I know alot of people when their car over heats and they turn the heat on and it cools down it usually points to the thermostat..

 

Thanks for the ideas people..

blackwidow:
Is there any special way to bleed a dsm? I just run it with the cap off till the tstat opens and coolant starts rushing out (heat on full blast) let it go for 5 minutes and cap it up..never had a problem doing that.

scottY:
I ran it with only one fan for over a year (during the summer even..) and the gauge never budged. I guess I will get the logger on it and find out exactly what the temps are when the fan comes on and it starts overheating..

Also I've had a front mount for 2 years and never had this problem. Both cores were tube/fin. I suppose I'll try cleaning out the radiator, maybe pull the condenser out, and I want to make some ducting. Used to have some but I smashed it.

rairai:
guess I never tested it, if it comes down to it I will pull it and boil it to see what happens. thanks.

keep em comin guys, this should keep me busy today..

 

Found a leak today by the tstat housing/waterneck area. Fixed it and now the problem is worse. Here is where it was leaking, very slow not even a drip.


Here is the gauge where my fans used to kick on, and the temp that the car stayed at ALL the time.


Here is the temp it reaches now when the fan activates.


I don't know what I did...there are no leaks that I can tell...its holding coolant, the upper hose pressurizes, and there is no coolant being pushed into the bottle...

It hasnt really gone over the temp in the second pic yet. If I let it sit for long enough once the fan comes on it slowly cools it back down to the middle..


and sorry but I dont know the exact temps all this is happening..my logger cable is in pieces

any ideas would be great..

 

Radiator cap in good condition? Timing properly set? Right heat range spark plugs?

What temp t-stat did you get? I've seen 160F, 180F, and 195F offered for the 4G63. Maybe try going with a cooler one. Maybe you had a 160F or 180F before and now you have a 195F. Most of the parts stores carry the 180F ones, you'd most likely have to order a 160F.

EDIT: Looking at Rockauto.com, they carry 180F and 170F t-stats for your car, and they're around $10.

I dunno man, could be any number of things.

 

I have a tested working new 180* tstat. Don't want a 170 as I've heard they don't let the coolant sit in the block long enough leading to less heat transfer.. do have one of those pressure relief rad caps, I don't like it though so I am going to get a regular one now...along with new bpr7es NGKs.

Timing is set properly on 1g CAS. Car runs great. Doesn't seem to even push any coolant intothe bottle..

Thanks