rx7style

iTrader: (1)

In my 1986 GXL, I have never seen the temp. guage inside the car go above half. Last night, I noticed it was right up at "H", so I pulled over and shut off the car. When I popped the hood to see if it was actually overheating, the engine didn't seem to be emitting more heat than it ever has, but I did notice that the coolant overflow bin was over the full line, and just a day ago it was almost at the empty line. I could hear the gurgling of coolant too, and there wasn't any leaking anywhere.

I drove the car today, and the temp. immediately shoots right past half, and stays at about 3/4 while driving. If I drive hard or put the car at high revs for about 10 seconds, the temp. guage goes back up to hot.

Is this just a thermostat problem, or could there be a larger [and worse-er] issue here? Maybe my water pump is dead??? Please tell me what you think the problem might be. I'm not going to drive the car until I figure out what's going wrong with it.

HENRX7

I have been dealing with the same problem for about a year now. I have the same model, a GXL. I think most of the GXLs suffer with this problem. Anyway, I already replaced everything you can imagine just to fix it but I am out of luck. Here are the parts that I replaced:

Water pump
Thermostat
Temp Sending Unit
Radiator

But according to one of the trusted RX7 mechanic here in the bay area, Rick from RRP, my temp gauge is faulty because when he took a reading using the water temp meter, my temperature is within the normal range.

So I went and bought a new Autometer temp gauge that also comes with a non-compatible temp sending unit to make sure that I will get the right reading. But as of now, I have not installed it because I don't know where to place the temp sending unit.

So check your gauge and make sure that it is working properly before you spend $$$ for the parts that you don't need to replaced!!!

HAILERS

I feel the need to scare somebody to death. Your car has all the classic symptoms of seal gone bad(or a collapsed seal groove). Buy an brand new radiator cap. Fill the radiator and bleed it. On the car I have there is a plastic plug on the r/h side of the radiator that needs to be removed as you fill engine. Yours might be different. Make sure it is full. Now siphon out the excess water in the overflow. Leave only enough to get to that bottom line. Now make sure that the hose that goes to the overflow is tight on both ends.This is to ensure that after you run the car and it cools off, the water that went into the overflow will now be sucked back into the engine. Drive it for an half hour, then let it completly cool off. Did the water suck back in the engine after cooling down to room temp? When you run the engine just sitting there does the engine pump water into the overflow. Rev it up and see if it does. Thats why rx are refered to as waterpumps sometimes. An aftermarket gauge would be helpful.Deep down I think you now have a waterpump. Not good.Worked one day, bad the next.I assume all the belts are tight.

rx7style

iTrader: (1)

Actually, here's what I just did today. I drained all the coolant. There must have been an airlock because when I opened up the air-bleed valve first, nothing came out. Then, I did just what you had mentioned, and filled the rad. up full with the bleed valve open. I'm sure it was completely full, and the overflow bin was at the "full" line exactly.

I just drove the car around for abuot 10 minutes and got it pretty warm. The temp guage went up to about 3/4 but never got any higher than that. However, as soon as I parked the car and got out, all I heard was gurgling and the overflow bin was filling up and went about 1.5" over the full line and then it stopped. Does this mean I have a bad seal? Is my engine toast?

Scott 89t2

sounds like you blew your head gasket. oh wait...

I would change the thermostat and see what happens

HAILERS

Yeah. Try a new thermostat alright. Just maybe that is all it is. I know just enough to know that the water temp gauge is very unreliable. Had one car that the needle was just over half way and another car that the needle was less than a quarter. Installed a aftermarket gauge on both cars and found the high temp car was actually colder than the one that showed less than a quarter! Very same aftermarket gauge on both cars. Swapped back and forth. Usually a waterpump will continue pumping water into the overflow as long as it runs.Caused by exaust gas continuing to enter the water jacket and displacing the water.Water usually heats up inordinatly quick.Yeah, maybe just a bad thermostat.Maybe not.

HAILERS

Just one more thought. At the end of the day fill the radiator up. Run it for say ten or fifteen minutes. Shut down. Lossen all the plugs but leave them in. Next morning go out and pull the plugs. If any water comes out of the holes........duh. If no water, go a step further and disable the fuel pump, then with the plugs out have someone whip the engine over and look for a water mist coming out as it is rotate.Actually you could just sorta bump it over and look for water. Do not mistake fuel vapors for water.

rx7style

iTrader: (1)

I actually just went outside and took a look at the car again, and the overflow bin has returned to the "full" position. So, the coolant drained out into the bin right after it was shut off, and since has drained back into the engine. Is this good or bad?

Oh yeah, and just a few months ago I had the exhaust analyzed and there was absolutely no coolant in the exhaust, so that means it can't be leaking into the engine. And it isn't leaking onto the ground either...

Scott 89t2

ya but your car wasn't bubbling or overheating a few months ago either... just because it wasn't comming out then doesn't mean anything now.

RX7nCRX

I didn't read all the posts, but replace your radiator cap, end of story, I've seen this plenty of times. Its a couple $$ and you can get one anywhere. Also, if you want, replace your thermostat while your at it, and always purchase your thermostat from the dealer, don't use aftermarket.

That should fix your problem.

HENRX7

I bet ya it's the gauge!!! Don't trust the crappy stock gauges.

rx7style

iTrader: (1)

You've seen this exact problem before, and all that needs to be done is replace the radiator cap? Everyone seems convinced it's the thermostat... I don't have any clue, but I'd sure be happy if it's only a radiator cap needing replacement.

HAILERS

It sounds promising, the coolant going back into the engine. Could be I was wrong about this being a water pump. Do the thermostat and the cap both. Then try to get an aftermarket gauge to see what the real temp is. If you do not keep losing water then it hopeful. A leaking radiator cap or the hose from and to the coolant tank could prevent the coolant in the overfill tank from sucking back into the engine during cool down. Gotta go.Sorry if I scared you. Not intentional. Sounded at first like a rotary water pump. I'd still pull the plugs in the morning and see if there is any water in the plug holes.

SureShot

My 87 (at 180000 mi) was showing the same symptoms. What finally fixed it? Would you believe the water pump housing? The aluminum casting behind the pump was eroded by the turbulence of the high revving pump. The bypass valve seat under the thermostat had about a 4mm chamfer eroded away, and there was a 6mm hole eroded through the wall between the inlet and outlet side. All this bypassing gives symptoms like a partially blocked radiator. I fabricated a repair with Bondo Marine Epoxy Putty Stick. It has held for a year now.

HAILERS

Mr rxystyle. God has punished me for trying to scare you in my first post. My 87 n/a buzzer went off two days ago. Low on water. Overflow tank brim full(should not be). Took the thermostat out completly. Swapped the radiator cap with the 87turbo, refilled the radiator and depleted the overflow tank to its hash mark down near the bottom of the tank.On the 87 n/a made sure the hose between the overflow tank and the filler device was ok and tight. Went to work in the turbo. Came home in the turbo. Slept.Got up and drove the n/a. No buzzer. Went to go to work in the turbo. Buzzard went off with a vengence.Conclusion... the radiator cap was no good on the n/a. Been punished.Hope your problem was nothing more than that.