cooling issues..., fine when driving, spikes when stopped. Options

[malaga_red75]

subaru JDM EJ25 DOHC

So, got my conversion finally road worthy and have noticed that while I am driving around, the car stays at around 200 F. when i stop, or let it idle in my garage... the temp slowly climbs and doesnt stop (i shut it off around 230 F). I am assuming this is an issue with my fans.

I am running a front mounted radiator, using 2 push-style fans. A few things that i think may be wrong...

-There is no shroud around the fans... just the shroud that seals the radiator to the front (since they are push fans, they are mounted on the front side of the radiator, in between the radiator and the nose of the car)

- there is about a 1 1/2" gap between the fans and the radiator (this was just the way that ended up working for mounting the fans)

anyways, i am pretty sure that the cooling system is working (no kinked lines, thermostat working, fans do turn on) as indicated by driving and the temp staying cool, there is just something not working when i stop moving. let me know what you guys think.

-Peter

[malaga_red75]

well, new thermostat installed. no change... well, id say maybe a 5 degree difference while driving, now around town I am probably steady at around 195-200 moving a littler faster it drops to around 185-190. stopped, it goes to about 215. my local shop said that they can sniff for hyrdocarbons at the radiator and determine if there is exhaust leaking into the cooling system. I will be doing this on tuesday morning.

One other note:

I have been reading online and on other forums and it seems that normal engine operating temperatures are between 180-220. But most of you guys say that you are running between 150-160 while driving. just curious what some thoughts are on this.


-Peter

[Mike Bellis]

well, new thermostat installed. no change... well, id say maybe a 5 degree difference while driving, now around town I am probably steady at around 195-200 moving a littler faster it drops to around 185-190. stopped, it goes to about 215. my local shop said that they can sniff for hyrdocarbons at the radiator and determine if there is exhaust leaking into the cooling system. I will be doing this on tuesday morning.

One other note:

I have been reading online and on other forums and it seems that normal engine operating temperatures are between 180-220. But most of you guys say that you are running between 150-160 while driving. just curious what some thoughts are on this.


-Peter

having temp fluxuations is fairly common with a conversion car. Some go as far as removing the thermostat. Removing it will keep the tamps more consistant, instead of up/down. It will take longer to warm up in the winter if removed. Since everybody has a different cooling system, even with the same engine. It's hard to say exactly why you have a problem. I could be as simple as you needing a new water pump. There are electric in line pumps that can be fitted if flow is your problem.

Since your car does not overheat while moving, your problem is either flow or air. 90% of the time it will be air. When you have all the air out, the problem is flow. Here's where it gets tricky. You can have a problem with both too much and too little flow. Too little, the water does not get cooled fast enough and hot water is returned to the engine. Too much and the heat exchanging effect will not work and hot water will be returned to the engine. At this point, you should try removing the thermostat and see if it helps. This should increase flow. If the system cools down, your system has too little flow. If the temp goes up, you may have too much flow. At that point try to pinch the hose aome to restrict flow. I would suspect too little flow is your problem.

To cure to little flow... Remove thermostat... or... Inline Water pump... or... Smaller pully on the water pump... or... larger pulley on the crank. Also look for any natural restrictions in your hose, kinks, bends etc...

[budman5201]

one question, how many return lines do you have that recirculate water around the engine when the thermostat is CLOSED?

What happened when you did the boiling test with thermostats ? old vs. new?