After I upgraded to a 55 engine I found the cooling to be marginal on the road and didn't dare take it too the track until it was sorted. The radiator is on the small side for the application, but the 2 things that make it worse for the W202 are the small engine bay and that the transmission cooler which is feed by hot water at the back of the block is then fed back into the lower radiator hose without being cooled at all.

I initially thought about using a W203 C32 heat exchanger as an additional radiator to put between the transmission cooler and the lower radiator hose to prevent hot coolant going back the the engine uncooled. It might have worked but i decided to just do it right and upgrade the radiator and leave that as a backup in case I needed more cooling.

I originally had minor overheating issues at idle but my main issue was at high speed on track so no fan upgrade was going to solve a cooling issue at 80-130mph. Under circuit racing conditions there was a greatly increased heat load coming from the engine oil and the transmission oil so any heat I could get out of the coolant would also drop my oil temps as well.

I had a custom PWR radiator built. It has a 68mm core compared to the 35-38mm core the factory radiator has. It added about another 2-2.5L to the total coolant capacity which always helps and certainly has more than enough capacity to keep everything cool. The only down side was that I could no longer run the main engine fan and I had to install a remote P/S oil tank due to clearance issues. The engine now actually runs cooler without the mechanical fan than it did with the stock engine and radiator at idle and low speeds. It is also much cooler on track (down to 100C). Next I need to look at an airflow problem in the engine bay, there is a big pressure buildup under the bonnet at high speed.........I'll let you know how I go on that one.

I wouldn't suggest this as a average upgrade, just thought I'd share a solution to my specific problem.

Awesome! May have to go down that path at some point. Doesn't look like there would even be room for an electric fan on the engine side. You going to add a pusher fan to the front or leave as-is?

One thing to just keep in mind and maybe it's not your problem, but your condenser can get really blocked up with road grime and bugs over time and seriously reduce air flow. I replaced mine with a new one and noticed I almost never hear the mechanical clutch fan anymore. I drive my car alot in the summer with the ac blasting and it can get pretty hot and humid, temp needle never goes over 85 and is almost always parked at 80. If you condenser is plugged up it will affect your radiator just the same. I'm just saying because I have absolutely zero cooling issues, my car cools great no issues.

Very interesting upgrade and perfectly understandable if you are tracking your vehicle. True, oil temps are a major contributor to heat issues which need necessary management.

I absolutely agree. I replaced mine about 2 years/8k kms ago.
I'm just greedy and expect to be able to do a track day in 30-35degC heat while using the A/C
The 2 factory aux fans seem to be doing a good job. I'm watching the temps on the A/C panel whilst driving and stationary, all seems fine. IF I have a problem in higher ambient temps I'm going to wire up the fans so they will always run at minimum speed.

I did 15 laps of the nurburgring over 3 days in my c55 with standard radiator I had no cooling problems at all.

I guess "Ausmbtech" not talking about cooling issues, he want to give more efficiency to upgrade the COOLING SYSTEM..!,

more life for Engine & everything around,

+1 cool = +1 hp, as a happy end track..>>>

ZAYED,,