86 Runs Hot

[MY86092]

Looking for advice on a recent car I acquired. I live in an area where temps are 90 - 100 during summer. I picked up an 86 Saleen that has a 331 crate motor. Radiator appears to be the original stock one. Coolant level is good, radiator looks to be in good shape.

Issue is this: On a hot day I ran it up the freeway to see how it handled the weather. Seemed fine, gauge sat in the middle, slightly above middle at times. When I took an exit and stopped at the light, gauge jumped way to the right while sitting there idling, almost pegged. Got back on the freeway to head home and went right back to normal. So it is fine with a good airflow, but idling on a hot day is not good. I fear that if I got stuck in traffic I would be screwed.

It has A/C, although it isn't currently operational. Once it is fixed I plan to drive more on hot days, but that would cause additional heating so I want to address this first.

I am wondering, is this a result of the high performance motor? Is there an upgrade to these cooling systems that would make a difference, i.e. aluminum radiator, different fan, etc.,? Has anyone else run into a similar issue?

[KevinK]

Sounds like an air flow problem. Maybe tithe fan clutch if it real. If it’s not real then the IVR.

[JKengineering]

+1 on the fan clutch
Mike

[KevinVarnes]

What he said. Does this car have an electric fan or a clutch type fan? In either instance I'd look at that first.

[JacksAO]

If it’s the IVR ( Instrument voltage regulator) you’ll also see the oil pressure gauge and the fuel gauge acting the same way. All 3 gauges are powered from the IVR and they will all act the same ( high or low ) if the IVR is bad.

[emerygt350]

Cool! I didn't even know that existed. I assumed it was a bad ground. My gauges were doing this something awful but now they still go up and down in tandem every once in a while.

[emerygt350]

That said, check your fan too.

[KevinK]

That said, check your fan too.

The fan should not impede the airflow unless it’s hitting on something. It’s always a goos idea to check the plastic fans as they are prone to self destruct/crack.

[Ourobos]

Since it's a 331, it's likely .030" overbored.. That could be part of the issue, late model roller blocks are done by about .040" normally. Thin walls and ambient heat don't go well together.

I'd suggest R&R on a good 180 thermostat, possibly upgrade to a good 3+ core aluminum radiator if it's in the budget.

Most importantly address any airflow issues - air dam in place? Fan working properly - if electric is it moving enough air?

[emerygt350]

by fan, I mean make sure it is turning when it is supposed to.

[ashley roachclip]

No one mentioned the shroud ,,,that is the most important , for ensuring proper air flow at idle , along with the clutch fan .
Your car is equipped with factory air , so it will have a clutch fan .

[stangPlus2Birds]

Is there an upgrade to these cooling systems that would make a difference, i.e. aluminum radiator, different fan, etc.,? Has anyone else run into a similar issue?

A heavy duty/police thermal clutch will have less slippage, and therefore cool better.
Note, that also means a loss of HP (~~1-4 depending on engine speed, thermal conditions, etc)

As for cooling upgrade, yes. But, how much money and time are you willing to put into it?
A Ron Davis radiator and fan setup can not be beat!
But, you need to upgrade the alternator and wiring. And, have a good fan controller (I suggest ordering and waiting for a DCC controller).
So, you're looking at ~$2,000+, and a good number of hours for the upgrade.

Good Luck!

[ashley roachclip]

Nothing beats a copper/brass radiator , for thermal efficiency.
Have your factory radiator recorded if it is bad , or professionally cleaned by a radiator shop .

[jsfrv6]

Check your timing. The higher the initial timing the cooler it will run at idle... try it and see what happens. You can try it in your driveway and don't cost a dime!

[MY86092]

Thanks All, I will check the fan first. It does have a shroud, blades looked good. But I will watch and see that it spins when hot.

After that I may go to a bigger radiator, seemed to help on the older mustangs I have owned. I think the Ron Davis setup is outside of my budget for now though ;-o))

Third day of triple digits, so probably going to wait awhile. Thanks again

[erratic50]

Actual pressure in the coolant system makes a huge difference. Verify your pressure cap is holding pressure like it should. Your radiator hoses will be firm when it’s at operating temp.

16 psi

[emerygt350]

Actual pressure in the coolant system makes a huge difference. Verify your pressure cap is holding pressure like it should. Your radiator hoses will be firm when it’s at operating temp.

16 psi

excellent advice that.

[erratic50]

The most base timing my 86GT would tolerate with the radiator in perfect working order was 13.5 degrees before TDC. 14+ would make it overrun the cooling system even on a 70 degree day if I ran it long enough.

It would get damn hot on triple digit summer days in NE at 13.5 too. Really on the edge.

I went to a 19 psi cap and was rewarded with a string of blown heater cores....

I eventually went to a 3 core copper radiator and a mcparts version of the PI “HD cooling” fan clutch. I went to 14 the back to 13.5 degrees because I found the added heat in the exhaust introduced too much heat to the fuel system — vapor locking problems if I wasn’t standing on it constantly in 3rd gear, etc.

ive always ran a 192-195 thermostat except for a brief experiment with a 160 and a 180 where it got absolutely terrible mileage. EFI hates the colder thermostats.

[emerygt350]

I have a motorcraft 195 in mine, CFI mind you, and I am at 12 degrees advanced. Not a 331 of course. Using a laser temp gauge I get 180 from the thermostat housing after long hard drives. Course, everything is working as it is supposed to be, or at least the computer thinks it is. I have a crappy old radiator and a cheap clutch fan. Cools off at idle in traffic at 90 degrees ambient temp.

edit: I should mention that when my PIP was going and I had codes coming from my ECT and IAT and MAP due to grounding issues the engine got incredibly hot. Dangerously hot. After fixing the ground and and PIP it runs as stated above, which it did before those issues.

[banzaibullitt]

+2 on the fan clutch. The fan clutch leaking it's viscous oil? Mine showed signs of a seep around the shaft, so I replaced it with a HD one along with my sticking thermostat. No issues since.

[MOOSH]

I upgraded to a 130 amp alternator and installed an electric fan from a 2002 V6 mustang. And my overheating problems are gone. I'm running a stock 302 with GT40p heads right now. Stock radiator, 190 degree thermostat. I can sit in a parking lot with the engine idling A/C on max during a 100 degree day all day long. Everything I used came from a local pull-a-part except for the fan controller.