How can I get my m20 to run cooler?

[CreamE30]

Hey all,

I've got an M20 thats getting a bit up in miles, and I've noticed that very steadily, over the course of about 4-5 years, the normal operating temperature has gone up. When I initially did the timing belt/water pump replacement, it would run at just above the first hash mark, now, several years later, its running near or at the last hash mark. Is it just time for me to replace the water pump (and the timing belt while I'm there) again? Or is there something else I could change out or freshen up to help it run cooler?

[BergerNJ]

if your close to the quota for a refresh then yes...


when was the t stat changed last? could be opening less

when was the last time you flushed the rad? could be buildup and the surface area is slowly getting smaller and smaller

[cabriodster87]

*

*I concur......

[danielmp]

Agreed, thermostat and radiator. Check your fan clutch. Lots of people get the 75 degree thermostat but the car came with 80 degrees so that's what I stick with. Sounds like if it's running at the last hash routinely you need to take care of it sooner rather than later, definitely not normal.

[strad]

Well having purchased a car with a mostly non-functional cooling system (my M20 cabrio) I can say that you'll have to go down the list. First I fixed the busted-open thermostat (that fix got the heat working again lol), which exposed the non-working fan clutch (and non-working aux fan lol) and somewhere in there I also had the radiator professionally flushed by a rad shop.

After that it ran so cool that I had to go back to a 80 C stat. I had gone to a 75 b/c I initially thought that's what was going to be necessary to get it to run cool enough lol. Turns out that a properly functioning E30 cooling system keeps the engine happy as can be lol. Now it runs between the first mark and the middle mark. And it'll run there with ambient temps at 115 degrees in the middle of a Las Vegas summer.

[stamar]

um if its that hot i bet you have air in the system and need to bleed it.

e30 water pumps, the orignal ones, are plastic vanes and silent. it could be going out with no signs so you cant eliminate that.

[TurboJake]

I would just start at the humble T-stat and go from there.

[dnguyen1963]

drill a small 3-4 mm hole on the top of the t-stat...helps with bleeding any trapped air.

[BergerNJ]

Well having purchased a car with a mostly non-functional cooling system (my M20 cabrio) I can say that you'll have to go down the list. First I fixed the busted-open thermostat (that fix got the heat working again lol), which exposed the non-working fan clutch (and non-working aux fan lol) and somewhere in there I also had the radiator professionally flushed by a rad shop.

After that it ran so cool that I had to go back to a 80 C stat. I had gone to a 75 b/c I initially thought that's what was going to be necessary to get it to run cool enough lol. Turns out that a properly functioning E30 cooling system keeps the engine happy as can be lol. Now it runs between the first mark and the middle mark. And it'll run there with ambient temps at 115 degrees in the middle of a Las Vegas summer.

exactly.....the cooler t stat is really unnecessary and just a band aid to a bigger problem.

you don't need to bleed the system if its been closed all of this time....

Id check the fan clutch and t stat first.....if everything seems ok then it could be a rad that needs a flush...

When was the the exact date/mileage of tbelt and water pump change? That should explain a lot too.....If youre in the ball park, Id go again and then throw a new fan clutch in.

[jeffnhiscars]

I've read enough threads about cooling etc and have never once seen mentioned something that I try to do routinely and absolutely do whenever my radiator is out. Go to Home Depot and spend $5 on a can of Coil Cleaner... yes, thats what its called. You use it on the outside of your radiator and while you are at it do your oil cooler and condenser. If you can shop at an HVAC supply house they will sell you a 1 qt spray bottle for $10-12 which will last eons.

Cleaning coils is recommended annually for your home AC which does not move down the road at 50mph gathering bugs and other crap so think about the insulating layer you have on your radiator fins whose sole purpose in life is to dissipate heat.

Last time I did my house AC the air coming out of the registers was dramatically cooler and my electric bill dropped big time.

Imagine what it can do for your car.