msmcgill

I've recently been having some overheating issues with my '84 GS. After perusing the forum, it looks like the intake manifold o-rings and gasket may be the problem (I hope!); with the tell-tale accumulation of leaking coolant on top of the rotor housing. Anyway, in an effort to troubleshoot the problem, I installed an aftermarket (Autozone) thermostat that supposedly opens at the OEM recommended temperature. Most of the threads I've read on the forum since seem to discourage using aftermarket t-stats. Is there a reason for this? Does anybody have first hand experience (neg or pos) with aftermarket thermostats? Thanks!

eddierotary

iTrader: (7)

i have a 180 aftermarket thermostat and it stay verry cool , i dont have any issues of it

RotaryRevn

the aftermarket's I have seen just didn't seem to be as good a quality and didn't have the little hole with the "wobbly" piece in it.

mazdaverx713b

iTrader: (91)

the "wobbly piece" is an air bleed valve. that is a good thing. i stick with 180 degrees thermostat. great results for me and my driving

Pele

iTrader: (28)

I've always used aftermarket thermostats in all sorts of cars... If the OEM one had a air bleed with wobbly pin the replacement did too... Especially Stant brand ****...

I think it's something else... bypass something or other.

Rx7carl

Yes, as long as it has the extension on the bottom for the bypass hole, your ok. If it doesnt, then youll have coolant bypassing the rad and continuously circulating through the engine, which is bad obviously.

msmcgill

That's why I started this post. The t-stat I installed (AutoZone 412-180 3398) is rated at 180 degrees; but is missing the jiggle pin that the OEM t-stat had. The Mazda Workshop Manual says: "Install the thermostat so that the jiggle pin is postitioned on the upper side; if it is not, the valve-opening temperature will change." That is what has me concerned. Also, I am not sure what you mean by your comment about the extension on the bottom. I thought every thermostat is designed so that when it is open, the coolant circulates through the radiator AND engine and when it is closed, the coolant circulates only in the engine cooling passages. Am I wrong? Should I yank this t-stat? I don't see how AutoZone could market their product for Gen1 RX7s, if it is going melt the engine. It seems like they would be risking losing a lot of customers - not to mention inviting a bunch of law suits.

Jeff20B

iTrader: (13)

I drlled a 1/16" hole in mine where the jiggle pin would normally be.

Rx7carl

I use autozone t-stats in both my cars with no problems at all.

msmcgill

Thanks Rx7carl! That is encouraging. I am assuming that you have some form of a Gen1 RX7 with one of these AutoZone t-stats installed? I've got to install those new intake o-ring seals when they come and flush the system out really well before I try to drive mine again. It was running intermittently hot before I discovered the source of the leak.

Fuel524

did you check to see if your fan clutch is bad????

msmcgill

Good point. Not yet, but I've been planning to. It does have a fair amount of resistance when cold, though - which is a good sign.

elwood

iTrader: (1)

The thermostat only has one function in life -- to open when the coolant at its back end reaches the rated temperature. This makes it easy to check if it's working properly. When your engine reaches operating temperature, simply remove the radiator cap (be careful, and pause at the pressure relief detent, so you don't burn yourself). If you see coolant streaming by, the T-stat is open and working -- if you don't, the T-stat is closed and bad.

msmcgill

True. But I think the question here is: does an AutoZone 180 degree thermostat open at the RIGHT temperature without the "jiggle pin" that the OEM RX7 thermostat has? If so, why is it on there in the first place? Right now, I am wrestling to try and get the stubborn banjo bolt off of the oil cooler so I can replace the seals...but that is a whole different thread. After I get the oil cooler leak repaired and everything back together, I'll be in a better position to finish troubleshooting the cooling system. Thanks!