New aluminum radiator, M3 running cooler - Great Success

[france320isco]

While this may be common knowledge to most here in regards to swapping in an all aluminum radiator, I was very pleasantly surprised when I was on the highway yesterday and my temps didn't creep a little past half like they normally would do. IIRC the temps only got in between the first and middle mark.

I'm not sure if the radiator is just really a lot better than stock or if my OEM one was messed up or clogged (I replaced it since it was leaking), but I'm thoroughly enjoying the fact that if I do have a problem, I should have plenty of time to see it while driving rather than always being a needle over half.

I read that a needle over half is normal though, do you guys normally drive like this?


The radiator I ended up getting was on eBay: http://www.ebay.com/itm/290792109516 I thought I was getting the Mishimoto but was comparing several and accidentally ended up having this one in my cart with some other items. Two small modifications were needed, the small brackets where the bottom of the radiator sits needed to be ground down a tiny bit, and the fan shroud needed some material taken away for the new radiator's drain plug (bottom center). If I were to do it again, I would get the Mishimoto just because of the warranty. So far, this one has been great, but time will tell.

On a side note, I also got the HPS silicone hose set and I'm impressed with the kit as a whole. It's nice getting the clamps with it not for an extra charge: http://www.ebay.com/itm/230889142113

I've recently re-installed the stock radiator because during the past three years running on the MISHIMOTO I wasn't able to spot any relevant changes in temperature values from the IC while driving.
What changed was the temperature change rate e.g. during warm up that takes more time and was causing the engine to be leaner in this phase (I have a lamdba gauge).
The same issue (which depends on the stock mapping of the warm up enrichments) is less severe with the stock radiator.
Obviously the car is mapped on the stock radiator specs in terms of coolant temperature.

I was also a little (just a little) worried about the possible increase in the thermostat opening/closing cicles.
While it was taking longer for the car to warm up, the cooling was faster e.g. during a descent at high speed and low rpms.
This was causing the thermostat to close, which rarely happens with the stock radiator on the same driving conditions.

I don't think the oil temperature was influenced too, with exception, maybe, during warm up.

[RAD2LTR]

Hmm, it's worth checking that theory out though now it's not going to half way at all. I haven't really sat in traffic yet though.




So you're saying a bit above the first mark is normal?

On my car it is. I'd say a needles width higher than the first mark is where it sits when its up to temp. The only time it gets to the middle is when its sitting and idling for a long period of time.

Will

[tonerrrr]

Also worth mentioning a temp needle sitting after middle bar could mean an old head gasket letting some blow-by.

Hmm, it's worth checking that theory out though now it's not going to half way at all. I haven't really sat in traffic yet though.

With the stock radiator, at 80 mph in 100 degree heat, the needle sits just above the first mark, nowhere near the halfway mark. It will creep up to the halfway point if I sit at idle for 15 minutes or so, but as soon as the auxiliary fan kicks on, it drops right back down to where it should be.

Will

So you're saying a bit above the first mark is normal?

[Whee30M3]

Normal or not I really didn't like the creeping over halfway even if only by a needle, does yours do that?

Mine would stay mostly at halfway, creeping a needle or two past from time to time. I pulled the gauge cluster, cleaned and tightened the grounds, and then put it back in. Now, the normal position is about two needles below halfway....

[RAD2LTR]

With the stock radiator, at 80 mph in 100 degree heat, the needle sits just above the first mark, nowhere near the halfway mark. It will creep up to the halfway point if I sit at idle for 15 minutes or so, but as soon as the auxiliary fan kicks on, it drops right back down to where it should be.

Will

[kiko]

My experience repairing euro cars (no viscous = higher strain) most of these cars on the road unless its been replaced in the last 8-10 years have the radiators in less than optimum condition and cooling capacity of the system is borderline on these cars (specially Euro versions).

So in your case it was probably a bit of both (bad rad + extra cooling). I fit upgraded on all of these cars going to hot climates, its a must in my opinion.

Also worth mentioning a temp needle sitting after middle bar could mean an old head gasket letting some blow-by.

[Brandon]

If I recall, my temp is always rock solid at 12 o'clock and never a hair over.

[tonerrrr]

Normal or not I really didn't like the creeping over halfway even if only by a needle, does yours do that? I too have read that the OEM one was more than capable.

I recently replaced my buddy's '85 944 OEM radiator with the OEM one and his car is now running cooler as well which leads me to believe somewhere in the 20+ years the radiators just get gunked up. His was leaking as well as mine so a "flush" was not an option for us to test out the clogged up theory.

[Brandon]

Folks consistently say the OEM radiator is fantastic and more than capable, even for hard track use. I did quite a lot of research before replacing mine and decided to stick with OEM. The other alternative I considered was a BeCool aluminum radiator, but I couln't justify $700 when the OEM unit was universally praised, even if the BeCool is a work of art. I read that the Mishimoto units are known for leaking. If your eBay unit works for the long term, then good on you.

[tonerrrr]

While this may be common knowledge to most here in regards to swapping in an all aluminum radiator, I was very pleasantly surprised when I was on the highway yesterday and my temps didn't creep a little past half like they normally would do. IIRC the temps only got in between the first and middle mark.

I'm not sure if the radiator is just really a lot better than stock or if my OEM one was messed up or clogged (I replaced it since it was leaking), but I'm thoroughly enjoying the fact that if I do have a problem, I should have plenty of time to see it while driving rather than always being a needle over half.

I read that a needle over half is normal though, do you guys normally drive like this?


The radiator I ended up getting was on eBay: http://www.ebay.com/itm/290792109516 I thought I was getting the Mishimoto but was comparing several and accidentally ended up having this one in my cart with some other items. Two small modifications were needed, the small brackets where the bottom of the radiator sits needed to be ground down a tiny bit, and the fan shroud needed some material taken away for the new radiator's drain plug (bottom center). If I were to do it again, I would get the Mishimoto just because of the warranty. So far, this one has been great, but time will tell.

On a side note, I also got the HPS silicone hose set and I'm impressed with the kit as a whole. It's nice getting the clamps with it not for an extra charge: http://www.ebay.com/itm/230889142113