Help - my car is running too cold
 

Due to heating problems I'd change my rad to a PWR rad and installed M-tuned's coolant reroute this summer. The new set up gave me great improvement and the former heating problems were gone (as long as I speak of coolant temperature since I still suffer from high IAT). On track this summer I had stable coolant temperatures a touch over 88 F.

But that was when we had nice summer temperatures. Now it’s getting colder and in temperatures around 37-40 F I face a new problem: I can't get my coolant temp to stay over 158-160 F when cruising. And it takes close to an eternity to get the engine warm (even with the heater turned off).

I have a 180 F T-stat that is working just fine.
Coolant/Water mixture aprox 50/50.

Anyone experienced similar problems? I was pretty sure that the t-stat was stuck open but it was working just great. Mayby I have to try to cover the rad. Any other suggestions?

Thanks!

Andreas

What is the diameter of the orifice that feeds your heater core?
-G-

Hi Greg!

Thanks for helping me out here. I hope I understood your question right here...

From the reroute adapter at the rear of the engine the oe hose runs to the heater core.

The t-stat has an orifice that my former 160 F t-stat didn't have. I’m not sure of the diameter though. But it's a tiny one...


Andreas

That little bypass on the thermostat shouldn't be an issue. I'd say double check that the thermostat isn't stuck open, and then count your blessings that you're not overheating and put some duct tape over the radiator.

I am having a problem with temps running too low as well. I have my fan on a switch, and I do not run it when I am cruising. If the car is not moving for very long the temps start to go up. The down side is, when the fan is on a switch, it is easy to forget to turn it on when the car is sitting and engine is running.

Cover half the rad, it's pretty simple

Paul has a problem with the Machine running too cool in the winter. He places a piece of plastic to cover like 1/3 of the radiator (maybe 1/2) and then he has no problems with temps.

I also put a blocker over the radiator. However, that's not enough, so now I'm wedging cardboard over 2/3 of the mouth. I'm jumping a lot more water past the thermostat than most though.

You never changed where the heater core outlets to, have you?

wat?

I'm wondering if he moved the heater core return to the upper radiator hose and not the lower.

If you route the heater core return to the top of the radiator instead of the bottom, you will have cold temp problems in cooler weather.

Thanks for your help guys!

In my eager to find more information I got stuck in the peter pan reroute thread... long read…awesome...

I'm sure of that the t-stat is working. I have no problems with the fan switch. I'll check in- and outlet to the heater core just to make sure they are as before the reroute. Next step is cardboard in front of the rad.

Thanks!

Andreas

I know. However, I can run all day long in 100* summer heat, under the SM lap record. I wouldn't have it set-up like that if it didn't matter. I'm going to throw a restriction in there and see if it helps a bit. I've even thought about sticking a ball-valve in there.

I would consider moving that return line to the bottom of the radiator. I don't think it would affect your warmer weather cooling.

I was trying to figure out why the car I was tuning last week took so god damn long to get up to temp, then i remembered he installed the begi reroute and put the return on the upper radiator hose. I'm having him splice it back into the lower.

That just makes no sense at all. The whole point of the re-route is to cool the hot water coming from the heater core. If you route it to the lower hose you are basacly doing the samething Mazda did in the fist place

The whole point of the reroute is to pull the coolant flow to top of radiator from the back of the head instead of the front, providing equal cooling across the cylinder head.

The heater core routing is peripheral...but can contribute to warmup and overall temp.

I designed mine like this for a reason. Returning hot water through the motor means its going to overheat on the track. There is a reason that proper racecars don't recirculate water like a streetcar.

If I only drove this car on the street, I'd have a stock cooling system.

wrong; that's not the point.