Join Date: Jan 2017
Vehicle: '02 SLK32 AMG
Other Toys: '05 SL65 AMG, '98 E320 4Matic Estate
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 52 Post(s)
Thanked 33 Times in 32 Posts
I had this issue once upon a time, and I can offer a few tips:
-The correct replacement pump is the Bosch '010', and as mentioned above, most other pumps draw too much current for the stock wiring to handle.
-Trace and check your IC pump wiring for cracks/shorts! This is a 15 year old car- these sorts of things do happen, and did happen in my case. Grab the digital voltmeter and check for continuity, proper voltage, and excessive ohms all along the way. This goes double if you've modified the wiring in any way for the E55 pump.
-When was the last time the cooling system was properly flushed and serviced? You may have a clog in the heat exchanger, or an air bubble in the system, which would certainly cause an IAT spike like you're seeing. It's a good idea to backflush each individual cooling system component and refill with proper coolant every 2 years or so.
-How clean is the intercooler itself? These sit right behind the big mesh grille in the lower bumper- the perfect spot for the fins to get clogged with bugs/rocks/dirt/debris, and they're barely big enough to do the job when they're spotlessly clean from the factory. An intercooler that is dirty can't dissipate heat, and could also account for IAC spikes. The proper way to clean it is to blow it out thoroughly with compressed air from the back, and then rinse with a garden hose (not a pressure washer!) from the same direction. I did this to mine, which wasn't that dirty, and I saw a 10-15 degree drop in IAT from this alone.
I hope one or more of these things help you get her sorted out!