Early to late radiator swap

[LTDScott]

I will be racing my early '87 325e LeMons racer next month in 100*+ temps and am thinking of everything I can to keep my car cool. While at an autocross today I noticed that the 325i staged in front of me had a MUCH thicker radiator. Mine is a single row (the core is only about half the thickness of the end tanks), whereas the 325i appeared to be a 2 row.

Reseaching reveals that all 9/87+ E30s changed to a different radiator set up, which from what I can tell is thicker and I would assume better at cooling. Has anyone swapped a newer radiator into an older (pre 9/87) car?

I can see that the radiator inlet/outlets are in opposite positions to the early radiator which would require new hoses and a "pipe" that runs across the front of the radiator. The mounts are different too. Anything else I should be aware of?

FWIW I have deleted the belt driven fan and have an aftermarket electric pusher fan on the front of the radiator.

I'll have to junkyard source all of this as a pimp aluminum radiator isn't in our LeMons budget!

[reelizmpro]

The water pump and coolant reservior.

[jlevie]

If the radiator is clean and in good condition as well as the rest of the cooling system being in good condition, the car won't have cooling problems with that radiator.

[LTDScott]

I'll need to change the water pump? Hmm, this isn't looking so appealing now. I don't really feel like changing the timing belt again.

jlevie, do you really feel the stock radiator is up to 14 hours of non-stop racing in 100*+ temps? The cooling system appears to be in good shape and we haven't had any overheating problems so far. We've replaced all hoses/belts/water pump in the last year, and I plan on gutting the thermostat so it just acts as a flow restrictor. The condenser, grille, and clutch fan/shroud have been deleted, so the radiator gets plenty of air flow.

[nando]

you can change the waterpump without changing the timing belt. you don't need the tensioner spring there as long as the tensioner is bolted down, it's only there to tension the belt while you get everything bolted together.

[LTDScott]

Looking into this, is there any reason to replace the water pump other than to hook up the overflow tank? Looking at the diagrams on realOEM.com, the only difference is that the early cars had an extra outlet on the water pump for the overflow tank, whereas the later cars used a complicated (and expensive) T-shaped hose to connect to the overflow on the driver's side of the car. Can I just use the existing pump and overflow or will it not work?

[smooth]

I've got a complete cooling system from an 89 up in Vista if you want to fart around with it.

[jlevie]

jlevie, do you really feel the stock radiator is up to 14 hours of non-stop racing in 100*+ temps? The cooling system appears to be in good shape and we haven't had any overheating problems so far. We've replaced all hoses/belts/water pump in the last year, and I plan on gutting the thermostat so it just acts as a flow restrictor. The condenser, grille, and clutch fan/shroud have been deleted, so the radiator gets plenty of air flow.

Sorry, I missed seeing this earlier.

I've not had any problems with my Spec E30 (an 87 325is) with the old style cooling system. The worst case was a three day weekend in 105-106F temps. On that weekend I did have three +50 minute sessions. Since then we've driven the car in three hour enduros in +90F temps with no problems.

So I'd say that a Lemons race probably won't be any worse as far as load on the cooling system. It will be lower speeds, so I'd make sure that I had a functional fan.

[NC325iC]

is your abs pump still in the car? it might be in the way of the overflow tank.

I dont know if this will work or not but i think the only difference in the water pumps is that the later ones have that t hose instead of the extra connection. It may be that you can still use that extra hose on an older WP and just change the rest of the hoses. Its something to look into for sure.

[LTDScott]

jlevie, thanks for the reply. I was hoping to hear from someone with first hand experience. While speeds will be lower than your racing, they won't be slow by any means. Last race we were over 100 mph quite a bit. The car does have an electric pusher fan that is connected to the temp sender on the radiator but has an override switch.

Is your car running a thermostat? Like I said, I'm thinking about gutting ours since we sure won't need any heat and a stuck t-stat out there would be fatal.

Converting the car to the later radiator would be possible within our LeMons budget if we use junkyard parts, but then we'd be gambling on the condition of the parts. At least I know our cooling system is in very good shape now.

I've also added an oil cooler from an i. That should keep the engine a bit happier. I'm just a little concerned about hitting something and damaging the cooler itself.

[LTDScott]

Oh and one other thing to consider is the fact that we are required to run water only.