Cooling - best upgrades?

[thornado327i]

Here is the deal. Eta-based stroker, Alpina C2 cpu, M20B20 head with larger valves, lightweight flywheel, everything else comes from 325i.

I'm happy with it - feels powerfull (breaks traction when reaching 5500rpms on 1st with 225 tyres - cool). The trouble shows up in cooling. After fooling around for just few minutes, the temp gauge gets to 3/4 of the scale.

Sooo - what would you suggest as an upgrade? It's not a track car, mind you, but gets it's share of action once in a while.

[slo325i]

Low temp t-stat, water-wetter with a good, clean flush, e-fan...

Mine's never reached the mid-point sitting in dead stop atlanta traffic in the summer heat

[thornado327i]

The traffic isn't that bad actually - just slightly crossing mid-point.

WTF is "water-wetter"? I probably know that, it's just that English is not my native language ;)

[jlevie]

The cooling system, if operating normally, should be sufficient., therefore something is wrong. A bad thermostat or air in the cooling system would be my first suspects. If the hot running occurs only when the car is idling, the fan clutch may also be a part of the problem.

[thornado327i]

The cooling system, if operating normally, should be sufficient., therefore something is wrong. A bad thermostat or air in the cooling system would be my first suspects. If the hot running occurs only when the car is idling, the fan clutch may also be a part of the problem.

I have no trouble with cooling when driving normally. I discovered it recently, as the weather provokes to fool around more - some drifting and my gauge shows 3/4 of a scale.

Oh, and radiator and fan also come from M20B20 - don't know if that makes any difference.

[Emre]

It sounds like your car has no problem with cooling while at idle or in normal street driving, but gets hot when you are really pushing it hard on the track. Is this accurate? If so, there are many possibilities.

Here are some common problems:

• Your radiator is not as efficient as it used to be. Maybe some of the rows are clogged up.
• Your coolant is suboptimal. Are you using straight anti-freeze, or a mix of anti-freeze and water? The more water, the better the cooling.
• Your oil cooler isn't working (or you don't have an oil cooler). A functional oil cooler is something that will decrease your engine temperatures on the track.
• Your thermostat is broken or opens at too high of a temperature.
• You have air in your system. Try bleeding it when the engine is very hot. If you continue to have air bubbles, it's possible that air is entering through a worn head gasket...or even a crack in the head.

These are the first things I would consider. Good luck.

[Kingb]

Water wetter is t3h shit. It is worth the $10. I don't think that pelican will ship to Poland but here is the link

http://www.pelicanparts.com/cgi-bin/ksearch/PEL_search.cgi?command=show_part_page&please_wait=N&make=POR&model=BE39&section=E39REC&page=12&bookmark=7&part_number=PEL-SW50189

[Knockenwelle]

Something else not mentioned yet is the quality of the water pump. Cheapie replacements often have stamped steel impellers, while the better ones have a well-designed cast one. The cheap impellers will not move as much water as the better pumps, and can actually cavitate at high RPM.

[thornado327i]

Allright. Thanks for help.

I'll look for air in the system - that'll be the first step. That, and the thermostat.

The coolant is 50/50 mix, oil cooler is ok, and getting Redline stuff here is... forget it.

I never saved on water pump, so I don't think that's the problem. The radiator itself is 20yo so I would bet on that.

Fun fact - this radiator has been into two frontal accidents (one serious - both in my previous car) without any damage! And by damage I mean leaks ;)

[thornado327i]

So after some checking:

1. T-stat is ok.
2. No matter what I do (well, enough for me at leat), temp wont go higher than 3/4 of a scale - won't overheat, but I think it's quite high, especially that the hottest days are still ahead

Two worries:
1. My radiator is really small! I'll have to measure it, but it looks smaller than 325i radiator.
2. One of my fan's wings, flaps, arms... e-dictionary check... BLADE - that's it. Anyway - part of it is missing - must have broken during one of my accidents from the past... What might that lead to? About 2" of a blade is missing...

[nando]

get a NEW 325i radiator. you're right to suspect the 320i radiator being too small, and also it could be old and clogged up.

the fan doesn't do anything at high speed - as you said, you aren't having problems with normal driving, only when having some fun, so that's not your problem. although having a peice of the blade missing isn't good, as it puts it out of balance.

[ethree]

I like the alloy radiators available from IE and others. I prefer the construction to the plastic tanks and you get about 1L extra coolant capacity. Might be worth looking into if you're going to replace yours anyway.

[DmcL]

a cheaper option for a bigger radiator is to fit an E36 318tds radiator. discovered the mounting points and inlet/outlet and overflow pipe are all in the same places but the 318tds radiator is just under an inch thicker and also about 4 inches wider. u will have to cut and shorten the lower mounting bracket infront of the alternator by about 4 inches but other than that it looks like it should bolt right in and clear the engine driven fan. also looking at it the top hose to the radiator looks like it should just be able to reach, worst case u can find a suitable size/shape hose from god knows what at a scrapyard.

[thornado327i]

a cheaper option for a bigger radiator is to fit an E36 318tds radiator.

I was thinking similiary, but about E30 324td radiator - quite huge and bolts right in (don't know about the hoses though).

Have to find some measurements.

Were E30 diesel cars ever brought to US?

[dashboardmonkey]

no E30 diesel cars here