so i just replace my water pump on my 91 N/A and took it for a ten minute test run, when i got back i checked to make sure there wasnt any leaks or anything and noticed that my engine seemed to be much hotter then it should. any suggestions as to what i should check out or be looking for?

 

You might have air trapped in the system. Take the rad cap off and start the car (turn heat on as well) and let it warm up. you can squeeze the upper/lower rad hoses and try to work out any air pockets.

Is the coolant level still good after the run? How hot is it running? Did you replace the t-stat? If so, what t-stat did you use (what temp)?

 

the coolent level was still good after the run, i cant really give you a figure of how hot it was, i didnt replace the t-stat either. i didnt think about it until now but could a bad T-stat cause a engine to run extreamly hot? ill try that air pocket trick you were talking about too.

 

Yes, a bad t-stat could do it (if it doesn't open, the flow won't go to the radiator). Did it run hot before the new water pump? Is that why you changed the pump?

On the temperature, I really mean in terms of the gauge. For instance, if it normally runs 1/4 on the gauge, where did it get to now? Did it get to "H" or close to "H"? If it was hot while driving, that means that it isn't fan related (the moving car moves plenty of air even if the fan wasn't working). If it got hot only when you were stopped, then that points to a fan issue.

Try to work out air pockets first. If you have air trapped, the coolant won't properly circulate and it can get hot.

 

ok I worked out the air pockets and it was still running hot, on my temp gauge its showing in between the half way mark and H. I'm going to try replacing my T-stat then and go from there. I heard that using THE OEM one is the best way to go. If this is true, where would be a good place to buy one? Mazdatrix?

 

You could hit up a local dealer. Might save time and money (once you figure shipping). I would use the OEM t-stat.

Let's go through the rest of my questions:

- Is it hot all the time? Only when stopped?

- Was it hot before the WP install?

- electric fan?

- Are belts the proper tension?

If you have an IR thermometer or even a meat thermometer, you could check the temperature of the radiator (which should be fairly close to the coolant temp). Normal coolant temperature should be around 180F.

It is possible that the gauge just isn't reading correctly, but if it read lower before the repair, then it isn't likely that is the problem.

 

did you ever get this fixed?

 

it seems to be hot all the time

i replaced my Wp because the old one was bad and the weep hold starting leaking (how it was when i bought it) so i dont really know if it ran hot before that.

no electric fan, just the stock one on the primary pully.

and all the belts are properly tensioned.

i feel like my temp gauge is correct because when i was driving it before i replaced the WP, it would show the correct temp.

my car has just been sitting since i posted this and i havnt done anything to it yet GSP David

 

It is a bit weird because changing the pump shouldn't have changed the temperature at all (or improved it, if anything). Besides the t-stat, the only thing that I could think of is that the connection to the water temp gauge has crud on it or got bumped/moved. This is on the back of the engine on the driver side and I don't see how it would have changed doing a WP install, but you might check that the connection is clean and tight.

When you drove it before (with normal temps), how much did you drive it and under what conditions (around town, highway, idle in the driveway, etc.)? I'm just wondering if it had the problem before, but you didn't see it because it wasn't run long enough to fully warm up or didn't see a high enough load to see these temperatures.

There are some tests in the FSM that you can to in order to test the gauge and sending unit. This would help to tell us if it is actually hot or it the gauge just thinks it is hot.

I think that I would pickup a new OEM t-stat to install and test the sender/gauge and go from there. Be careful and watch the temperature closely. We don't want to overheat the engine.

BTW: What mix did you use on the coolant? Usually 50/50 is good for most locations.

Something like a clogged radiator could also cause high temperatures all the time, but something like that wouldn't change so suddenly.

 

bleed your system asap, running hot is the WORST thing for a rotary

 

When I bought the car I drove it about 50 miles back home, Android about 35 miles was highway. I didn't try to push the car at all either. The rad was just put in brand new when I bought the car. I'm going to try replacing the t-stat next

 

And for the coolant? Did you use like 50% coolant (the undiluted stuff) with 50% water? Or just used the 50/50 premixed stuff off the shelf? Either of those should be fine.

That is plenty for the car to get fully warm, so unless this was a fan issue (okay on highway, hot when stopped or low speeds), then the temp behavior should be the same now as it was before.

The most llikely problem would seem to be trapped air in the system (since that should be the only thing changed between now and then), but you said that you tried to work out the bubbles (however, you may try again as sometimes they can be stubborn...run heater when you do it too).

If you think that you got the air out, the t-stat would be next (good idea anyway). I would also test the sender/gauge or maybe try an aftermarket gauge. This way you'll know if you are actually running hot or not.

 

when i get home today ill check the sender/gauge. i should be replacing the later this week or maby next week because i dont have the time to deal with it. but i would like to thank you for all the great information and advice. i dont know what i would do without this site haha