I know over heating threads abound right now during the summer, I've read them all and I have done everything y'all said.
83 12a gsl
1. New Radiator
2. New Fan Drive Clutch
3. New Thermostat (mazda 82 C)
4. New Hoses
5. Flush and Refill
6. Pulled out every hair on my head
7. Ran out of hair and starting pulling more painful hair

System overheats slowly. 1/4-1/3 up the gauge, choke releases. Will idle at about 1/3 up the gauge. Drive it around my neighborhood and it raises slightly. Drive it around town, gets to halfway. Let it sit in my driveway and it gauge constantly rises.

Took infrared temp on all parts of radiator.
At 1/3
top 187
bottom 193
at tstat housing 198

At 1/2
top 203
bottom 207
tstat housing 212

I haven't let it get any hotter than this cause I scared. Please help. Its too sunny not to be cruising to the beach with the sunroof off and the windows down.

 

have you checked the waterpump? it's not on your list.

Alvin

 

seems that everything pretaining to the cooling system is new except the rad cap and water pump. can't really see why it still runs hot. have u let it run at idle long enough to see if it'll get more than half way? as hot as it has been lately, it's going to run hotter than normal. it will actually run cooler driving it around since more air moves thru the rad while the car's moving rather than sitting still. make sure all the fins in the rad r straight and not bent over, plus flush any bugs and debris that r cought between the fins. make sure u have as much air flowing thru the core as possible.

 

water pump has not been replaced because it shows no sign of discharge from the bleed thingee and does not sound like the bearings are cooked. rxtasy, rad is brand new, and it heats up regardless of moving or sitting.

 

Still have the A/C condensor in front of the rad? If so, are the fins on it flattened, thereby blocking airflow?
I don't know about rotary engines, but on a piston engine, incorrect ignition timing can cause them to heat up.

 

right,
I'll check sparkplugs and the belts are right and tight. I'll check out the condensor. The a/c blew nice and cold last time it was used. It was disconnected (belt) after overheating began. Thanks guys.

 

Something else to think about is that if you haven't actually tested that thermostat in a pot of boiling water with a thermometer in it, it may be sticking and causing part of your overheating problem.

It's 116F today in Phoenix, AZ, and I've been driving my 84SE back and forth to work with the A/C running full-blast - not getting over 1/3, and that's with the original radiator (rodded-out last summer).

If you exhaust all options, have a look at your thermostat again. HTH,

 

The thermo is good, brand new mazda part. I just got a new radiator cap, I think that helped a little. BUT
I was checking out the rad and I unscrewed the level sensor and it is split. The top was just barely holding on to the threads. Got it most of the way out and the plastic gives way and no one carries it but mazda. Price tag?: $141. No, I didn't leave out any decimels. VB has it for $50.
Question...
Is it possible that the crappy plastic broken $141 pos has been causing all my problems?
Anything wrong with the VB sensor?
thanks again.
Oh and longduck,
I'm glad your cooling system works so well. wtf does that have to do with my busted *** one?

 

Damn man. I've been bustin around in this VA heat too. The only thing I can think of, is the water pump has cavitated so many times that the cavitation has eaten the impeller away. (I just saw a video of this at work). Cavitation is a creation, growth and collapse of air bubbles. When the collapse, they do a great amount of damage to metal. I think it would be worth while to at least take the pump off and take a look. Just buy a gasket for it.

For your question, I don't think the level sensor will have anything to do with how hot the car gets. I don't see how.

 

If it was leaking or something. I don't want to take off that waterpump and deal with the coolant anymore. I can't even drink water without throwing some green dye in it. I live the ****. The plugs didn't look to bad, but they were kinda weird. Two prongs were whitish, not bad, and two prongs were blackish, also not too bad. These are the trailing I'm talking about. Its gotten to the point that both me and the rx both want to dip our asses in cool water just to cool off in norfolk. If y'all think its the pump, I'm gonna take it in.
No mommie, I don't want anymore electric lime kool aid. Greggie's kidneys hurt.

 

Make sure that you have not lost your leading ignition. Running on trailing alone will heat things up in a hurry.....

Any chance you could take a couple of pictures around the radiator and the front of the motor?

 

I'll check leadings.

 

I had my radiator prof. cleaned and still had a problem. So then I bought a new one and it helped. I asked the guy who cleaned my rad. what was up with that and he didnt really give me an answer. I also had my belt slipping so I installed the dual belt system. Everything is back to normal. I think the belt slip issue was the main culprit.

 

If you need help pm me. I'm in P-town.

 

Call a different dealer. I just bought one of those sensors, for the same reason, and only paid $36. That even included an extra $3 for it to be overnighted, and a new rubber seal. And yes, I bought it at the only Mazda dealer within 50 miles.

 

leadings are fireing.
I think my compression sounds good too, btw.

 

Call a different dealer. I just bought one of those sensors, for the same reason, and only paid $36. That even included an extra $3 for it to be overnighted, and a new rubber seal. And yes, I bought it at the only Mazda dealer within 50 miles.
The lady at the dealer is an idiot. I bet she was looking at something else.

 

So to recap,
Belts.... check
tstat..... check new
hoses.... check new
radiator....check new
fins on ac....check
Rad cap.....Check new
fan clutch...check
fanshroud ...check
water level sensor.... junkyarding it today
beer and candy.....check
ball bearings....check (jeez guys, don't you know? Its all ball bearings now-a-days)
As for the water pump, I'll spend some time checking that out. I got me one of those roller thingees and it makes getting under the car almost fun.

 

Are you loosing any coolant? Or are there any other signs to confirm what the gauge is reading?

I recently replaced the temperature sensor (below and behind the oil filler neck) because the gauge started going unusually high. I knew it wasn't getting that hot because the electric fan wasn't kicking on. It is easy to check if it is ok, just remove the wire and check the resistance of the sensor. I can check the manual later for the spec if needed.

Good Luck
Bruce

 

I hate to say it, but it's probably something simple and maybe something you've already looked at and dismissed. Perhaps an air bubble or bad thermostat. Yes, I know you said you replaced it, but that doesn't mean the new one is any good. You MUST, as someone else suggested, actually test it in a pot of water on a stove with a candy thermometer. Is it installed correctly? If you put the jiggle-pin in the wrong position, any trapped air will have a hard time escaping. Did you have the cooling system pressure tested? What about the ignition timing? Someone suggested that and you, instead, reported the condition of the spark plug tips...that's not relavant. Physically put a timing light on the engine and verify the timing before you dismiss the possibility. Fan shroud on? Header panel in front of the radiator in place? No beavers damning up the front of your car? If there is a separate condenser in front of the radiator, is it blocked with leaves? Do you get any unusual pressure build-up in the cooling system? Have you tried flushing the cooling system...not draining, but actually flushing? Did you do it twice?

I sense frustration but, frankly, it has more to do with your approach to the problem than anything else. To be honest, throwing parts at a problem is the lazy way to fix it. I've done it myself and may do it again in the future, but then I kick myself when I replaced a $199 part that did not help when it was really the $1.99 part that was the culprit. All I had to do was be more diligent in troubleshooting and not cross anything off my list before truly ELIMINATING it as a potential cause. Easier said than done, but it's worth going the extra mile. All I'm saying is, try going about the problems in a different way and not only will you see more success but you can save a lot of time, frustration and money. And when you must replace a big/expensive part for the sake of eliminating it (presuming you did everything else first), then do it with a known-good used part that you can take back off if the part proves not to be the probelm. That's not critiscism, but advice from someone who's been there.

 

Ignition timing is a common cause of overheating.

Also, bubbles in the cooling system are dangerous, but in my experience bubbles manifest themselves as erratic temp readings. When I refill the cooling system I leave the cap off, start the engine, and check for bubbles and add coolant. Some guys like to jackup the frontend to encourage bubbles to migrate to the radiator top, but I've not found that necessary. The temp gauge should slowly climb to 1/3 and stabilize during this process, and fluid level should stabilize, except it will vary a little when you blip the accelerator. It could be that previously there were air bubbles in the system that allowed the water pump to cavitate and that eroded the impellers, so you need to change the pump. That may not manifest as bleed hole leakage.

B

 

run it without the tstat and see what happens....just a thought. when i had an overheating problem, and after i replaced everything, it would run cool without the tstat but overheated with it. now that I look back it was probably a faulty thermostat or maybe wasnt installed correctly, but ill never know for sure since the car is torn apart now (restoration)..

 

If you try that, be sure to install a big washer in place of the t-stat to form a restriction. Or, you can simply gut an old t-stat. Not doing so can undermine cooling system efficiency. The system needs a restrictor.

 

Thermo was tested. I guess I didn't itemize that. It had a cheap tstat on it so I have no idea where the jiggle pin is supposed to be. I figured it lets air escape so its at the top. Am I wrong about that?
As to loosing coolant, I don't think so. I don't smell it in the exhaust, and there is no smoke in the exhaust, other than right on start up. Maybe a second of it.
The radiator looked screwed. Bent fins, corrosion, and bent outlets, as well as a spot of jb weld at the top.
As for an air bubble, I've tried my best, but who knows? Thanks for the new perspective guys. I won't let you down

 

One more thing. Hoses are supposed to bulge slightly while under pressure right? I'm not talking fat girl in a haltertop bulging, just a little bit, right?