I'm having some issues keeping my rx7 cool under cruising/spirited driving, idling doesnt seem to be a problem. It's slowly creeping higher and higher on the factory gauge under easy or spirited driving. I've checked the basics but im not getting anywhere. I do not believe it's the coolant seals.

my setup: stock s4 na block, port matched tii intake manifolds, greddy cast turbo manifold, greddy td06 turbo, greddy wastegate, 3" turbo back exhaust, Godspeed fmic, Godspeed radiator, Ford Taurus efan, fd alternator, dual belt pulley, full emissions delete, premix at 100:1, 93 octane fuel, walboro 255 fuel pump, aem fpr, 900cc primary 1600cc secondary injectors, rewired fuel pump, innovate wideband, msd shielded wires, ngk 9's all around, rtek 2.1 using arghx timing map, lightly street tuned at 13 psi, afrs vary between 11.5-10.0 at full boost (rich I know, but if rather be safe).

I did have an msd 6a on the car, but it fried along with other wiring in the car. Symptoms seem to have started after that, but its hard to tell. I have an msd digital on it's way to replace it, though I feel like it shouldn't make a difference as far as heat goes.

car has the factory under tray and am upper radiator cooling panel.
Water pump is fairly new
no sign of leaking coolant anywhere(outside when it gets hot enough to come out of the overflow).
new oem Mazda thermostat
no smoke from exhaust
no bubbling in cooling system
new .9 bar radiator cap

I'm thinking that the timing may be too retarded.

shoot me some ideas guys, id like to sort this out and put some more miles on her this year.

 

What sort of temps are we talking about ?

How well sealed are any gaps between the opening in the cover and the radiator? Should have a clean duct with few air leaks. I used window ac sealing foam (not the adhesive kind) and 1 minute rtv to attach it to the underside of the radiator, certain areas of the under tray, and just pressed it into gaps around the radiator to help direct airflow through the radiator and oil cooler. I also have the stock air guides under the over flow and relays and to block off the headlamps.


Your front mount isn't helping things, really...

Has the fan got a sufficient shroud? Flaps to allow air to vent at speed?

Have you actually pressure tested the cooling system including the cap ?

Do you have heat shields or wrap around your turbine housing ?

If you're solely relying on the in dash gauge and the rtek, have you verified the sensors operate within spec and that the wiring between them and their component masters are in usable condition ?

What are your oil temps ?

Just a few questions... lol

 

I haven't bothered logging temps with the rtek and I'm basing this off of the factory coolant temp gauge. It's getting hot enough to force coolant out the overflow most times and has gotten hot enough to audibly boil a couple times.

there are definitely air gaps but none that ever caused a problem on a stock turbo which I ran the same radiator/fan/intercooler and didn't see heat issues.

overheating is happening even with casual cruising, it just comes up slowly.

fan is well shrouded. Flaps?

I have not pressure tested the cooling system.

Turbo has a heat shield, downpipe is wrapped.

I'll have run a log on the rtek.

questions are good!

 

is your efan shutting off after you start moving? your efan shouldn't be running after 20ish mph

 

Efan is wired to switched power; car is on, fan is on.

 

I feel like the stock fan and shroud more than adequate for your setup assuming you could make the shroud fit properly.. but I'm not going to start a cooling fan war.

The bypass flaps are intended to help air pass thru the shroud at speed, but it doesnt sound like your shroud has them.

Pushing coolant out of the overflow is usually a bad sign. Have you verified the thermostat is opening properly by removing it from the vehicle and gently bringing it up to temp?

In the short term if you're going to drive it, run the heater if you're going to encounter a situatuon where it'll get warm. The heater core is a second radiator and will easily drop the temps back down.

 

The fan was adequate for cooling my previous setup under spirited driving, I can't imagine it would suddenly become a problem for regular driving.

the shroud does not have a bypass flap.

I didn't temp test the t-stat, however the car is behaving identically as it was with the previous one i just replaced.

running the heater does help a little but not completely.

I know coolant coming out the overflow is commonly a sign of failed coolant seals, but where there's no bubbling or smoke I'm hoping it's not the case.

 

Hence the suggestion to pressure test..

Rent the tester, swap the pressure cap for a flat cap and pump it up. If youve got a leak, it'll show itself. If you cannot find a leak but the pressure still drops and you smell coolant from the exhaust next you start it, there you go...

When did this problem start? Did you change anything or install a new part ?

 

I'll give the pressure test a shot this weekend.

this started after replacing the wiring in the car (short fried the body harness) and removing a faulty msd unit. The car did a lot of sitting In between.
it could even be that the rtek was damaged by the short and isn't functioning 100%.

 

Looks like coolant seals it is! Thanks guys. Not what I was hoping for, but I've been planning to build a motor anyways!

 

That sucks man. It does happen, but its always unfortunate.

 

Sucks, but its better than it being an apex seal