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Discussion Starter · #1 ·
HELP!!!!!

I have a 2005 M3 Cabrio SMG with the all of the basic Turner Motorsports mods (intake, exhaust, pulleys, Shark programmer, Bilstien suspension, brakes, adjustable camber plates, etc.). It is my daily driver and I track it when I can.

I have a problem with the temperature going up, but in what is intuitively a backwards manner:

The oil and coolant temps gauges stay dead set in the middle of the normal operating range while in stop and go NYC traffic on hot, humid, heavy days and WITH the air conditioning on. The problem comes when I free up from traffic and can drive at roughly 60 miles an hour in third and fourth gears. This results in RPMs in the 3000-3500 range. This is clearly under very low engine load and with plenty of air coming through the front grill. It is in this seemingly kind and undemanding scenario that both the oil and coolant temps go up. The oil to just past the high mark of normal on the gauge and the coolant as high as into the red. If I come off of a highway and down to street speeds with a lot of idling at street lights the temp returns to dead center on both gauges. If I remain at highway speeds and turn off the air conditioning the temps both come down to some degree (oil temp to just above the high mark and the coolant still above the high mark, but at least out of the red), yet still remain unacceptably high.

I have spoken with the fine folks at Turner Motorsports and with my great guys at RCT Performance in College Point Queens NYC. We agreed that a flush and change of coolant might help. We opted to use a 60/40 ratio of water to to anti-freeze, with 8 oz of Water Wetter as a bonus. We even changed the oil and filter. This has not helped. The fan clutch seems good as the free spinning test at both cold (1 1/2 revs) and hot (3/4 of a rev) were what one would expect. I believe that the engine is truly getting hot due to the fact that both gauges indicate high temps at the same time and the temp returns to normal when conditions change.

This is baffling and I am hoping beyond hope that someone out there has experienced and fixed this. if so please please please let me know.



Thank you for reading,



-Joshua
 

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Check the water pump. Perhaps it is providing sufficient coolant flow at low engine speeds, but isn't up to the task once engine speeds go up. Also check your oil pump and oil passages to look for any pressure losses or flow obstructions. You might also check the thermostat.
 

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Discussion Starter · #3 ·
I appreciate the thinking DSilk

Stripping apart the front of the engine and getting at the water pump and the t-stat is the next step, though we had hoped to avoid the costs associated. I had also mentioned oil flow to both Turner and RCT, both thought not, but it will remain as a possible culprit.


Does anyone else have experience with this odd and seemingly backwards problem?
 

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its usually on the non M water pumps but ive heard that the water pump loses contact with its driven shaft at higher rpm of the engine which makes the fault work backwards in stop and go it can drive the water pump hence no over heating but at higher rpm it can not and increased heat of driving faster over whels the cooling system... i did a little research on the M water pump with the guys at my indy shop and it is suppossed to be a competley different and better design, i know it costs like 350$ ...ouch...
 
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