Hey all,

I've been seeing hotter temps these days from the water guage. When i got the car last july or august i used to run with a/c on high and parking lights on all the time, which kept the engine to ~180.

A month ago I was driving in traffic and it crept up to ~210.....I then got on the highway, but instead of coming down the temps crept up a little more....so I flushed the radiator that weekend and put in a 55% water 45% coolant mix. I also changed my filler neck cap, since the old one had a questionable seal surface.

Now the temps only get as high as 210 on a hot humid 95 temp day....even on the highway. They don't come down unless I blow hot air on full blast inside the car, which isn't the most pleasant thing to do.

I'm wondering this: Is the car normally supposed to get that hot in the summer with all the accessories on? I haven't done the fan mod, but I'm questioning how much that would really help since highway speeds don't seem to make a difference like they did before. I put in a downpipe over the winter, but I guess it's not helping as much as I need it to right now.

What else should I look at beyond doing the obvious mods? I'm wondering why going 80 on the highway isn't bringing down the temps like they did before....i've looked at the radiator fins, and nothing stands out in terms of airflow blockage. The oil cooler's pretty beat up though.

any thoughts?

Car is a '95 base with almost 63k on her, and i've only put on a downpipe and guages. Thanks for looking....

 

I don't think that 210 is bad. When you get to 230 is when you are going to need a rebuild. I run 200 for a while and then it creeps up to about 207-210. Yesterday it got to 214 which starts to scare me but I know its no biggie. If you want to keep it cooler in there do the fan mod, upgrade radiator, and vented hood.

 

right.........210 i'm not too worried about

it's when it starts creeping upwards of that I get edgy.

I just figured that the car would come from factory able to handle these sort of ambient temps.

My precat was a little clogged, and when i replaced it with the downpipe it fixed my boost pattern. Now the patterns getting a little funky again, and i don't know if it's the heat lowering the intercooler efficiency, or the main cat getting clogged (at 63k miles already?).

I'll try the fan mod this weekend and see what happens.....

 

You've already done the 'quick fixes' (flush, replace caps, etc). It may be time to replace the oem radiator. Mine was replace under warrantee at around the same mileage when I had the same symptoms and a new rad solved it.

 

did the radiator bust before you got it replaced? or can i call them up, tell them the problem, and bug them for a replacement?

 

If you are going to look into replacing the radiator, I would suggest going for an aftermaket one like a Fluidyne:

http://www.absoluteradiator.com/

 

absolutely!

i'm just wondering if anyone else has had experiences with aftermarket warranties on this type of issue.

I figure they'd rather replace something small and keep the car cool....otherwise they could wait till I blow the engine and dish out more money for rebuild. This is why I haven't bothered with replacing the hoses, AST, etc.

 

No, the radiator stayed intact. I was experiencing higher temps at rpms above 4000 rpm.
The mechanic experienced the higher temps on a test drive and there was no problem getting a replacement (albiet another stock rad).
My plan is to replace it with a Fluidyne in another year or so since I only have less than 10k miles on this one.

Definitely follow Mahjik's advise and get a Fluidyne (or Koyo).

 

It could be that your stock radiator is clogged up. Take it in to a radiator shop and have them un clog it. They burn it out in some kind of chemical that gets rid of all the bad **** in your radiator. I had it done and it now flows like it's suppose to. Flushing the coolant helps but if the radiator is obstructing the flow of the coolant , it'll still flow poorly and cause higher temps. Just my opinion.

 

hmm.. well, you've mixed entirely too much coolant in for your water/coolant mixture. Coolant doesn't cool as well as water because it doesn't dissapate heat as quickly (and it's harder on your water pump). I won't say that the mixture is 100% the cause of your problem, but that's entirely too much coolant.. Granted, you are in Michigan, so maybe it gets super cold up there (-15 F?), but still... I might think of adding some water in there for summer and more coolant for winter maybe?

 

i figured that the coolant was the issue as well.....I mean, the stuff i flushed out was more like 50/50 so I thought i was making a little improvement. The thing that confuses me is.......this same mixture gave me no problems last year.

I'm not sure, but I'm guessing my mixture is close to 60/40 right now, since I added only water after the overflow tank dumped out a bunch of coolant (problem was a bad rad cap, which i fixed)

Still, i'm just wondering what would account for a 30 degree overall increase in engine temps, when the only thing I really changed was the downpipe (which is supposed to LOWER my temps )

I think my next step will be to check out my radiator...

 

try new t-stat 1st.

 

yeah....a buddy of mine just told me the same thing. I'll try that first. What this about switching to a miata t-stat? Guess i'll search........

 

Don't overlook the condition of your oil cooler. If the fins are all bent over, then the oil temps will be higher, which makes the engine run hotter and the coolant gets the jobs of trying to cool things down. That is why getting ont he highway doesn't help. You are running a fixed RPM (about 2500) and the oil cooler is totally inefficient so the cooling system is working harder to saty cool.

Take a long pick and carefully straighten all the fins to maintain airflow THROUGH the cooler. It shoul dhelp the water temp stay down.

 

good point PaulyDee.....I'll take care of that soon and check it out on the highway again.

also, i searched but didn't find any info on changing out the thermostat. Does anyone have a link? I guess I can always check out my buddy's shop manual.