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Hey! I have a problem here That I need help with. I have just got done sucessfully installing a vj-11 turbo (8 lbs psi) in my B6 DOHC Engine. Everything has been sucessful up till this point. This one problem I have had since the install. I have noticed that before the install My temp gauge used to read 210 ° F. before the rad. fan would kick on, then would cool the engine down to around 180 ° . Now after the install of the turbo it climbs up to around 240° befor the fan kicks on. thing is, the fan dose NOT have a problem maintaining a stedy temp every time. it just seems that the coolant is heated up faster then the temp sensor can read. my sensor for my after market temp gauge is mounted on the housing of the top rad. hose. My lines running from the turbo are connected to the old lines from the Throttle body heater, I just disconnected the TB lines, for the turbo lines. Im sure that the engine is getting as hot as indicated , the engine bay is much hotter than before. Another problem I have noticed along with this is after the car has ran for a while, i hear a pulsating, light screech noise, not loud but noticable. Only when im slowing down (braking or not braking). I think this is some how linked to the engine running much hotter, I think its coming from the transmission. Fluid is full, and i have removed both wheels to check for rubbing, splash shild and checked the rotor nothing is out of spec. only dose this after the engine is warm. anyone have any idea to whhat the problem is or how to fix this ? one idea i had was to hook up both fans together, but then i think the problem is not the cooling down its the fan kicking on to late. So and help would be much appreashded. thanks ! Sorry for the long post.

It is common for the turbo engines to run hot i think - but things to check would be -
Air bubbles in the cooling system? Coolant temp sensor has sludge buildup? Engine running too lean? Sludge blockages in coolant passages? Timing issues? Intercooler not efficient enough? etc etc

thanks, but the thing that makes no sense is it will do that from idle. like ill start it let it run untill it heats up , not driving, and it will hit the same like 240 degrees every time before the fan kicks on.

Try a radiator flush and possibly replace the coolant temp sensor. I did a radiator flush myself and you wouldnt beleive the kinda crap that came out....

i second the flushing the whole thing. i flushed the whole motor and everything before i put my turbo on and there that stuff was Nasty! and i spose while you were at it you could change the thermostat as well then you wont have worry about that either. mine just went out like a month or two ago

Back flushing the cooling systemis a really good starting point. When you refill it I'd recommend using a 50/50 premix coolant along with a bottle of Red Line Water Wetter or the Pro Blend Coolant Mix. Also remove your thermostat housing, clean the coolant temp sensor or replace it. While the housing is off pull the thermostat out and replace it with a 170-180*F replacement thermostat. Other things to look for are leaves and debris stuck in front of the radiator or stuck in the cooling fins. Finally, go to Advance Auto and get a Stant 16lb-19lb radiator cap for a Mazda (I currently have a 16psi cap on my drag car). No it doesn't say Apexi, Cusco, or Mazdaspeed, but it does the EXACT same thing; they raise the cooling system pressure to around 1.3bar (18.85psi) which raises the systems boiling point and increases cooling capacity. These things will vastly help with cooling efficiency. When adding a water cooled turbo to the OEM cooling system you are adding a LOT of thermal stress to it. One other thing you can do is just leave the fan on when the car is on, use a SPDT 30 amp relay and wire it up to an ignition switched wire as the diagram shows (Radio Shack about $7). Also run a good 10w30 oil with 1 bottle of Lucas Heavy Duty Oil Stabilizer. That will help increase your engine and turbos life and further reduce operating temperatures. I LOVE the Lucas Oil products! If you still need more cooling capacity than that your only hope is a larger radiator and/or higher flow cooling fans, but I doubt you'll need them. I flogged the crap out of my drag car for over 10,000miles and the coolant temp never went above 210*F unless the fan was left off and then it peaked at around 230-240*F (my fan relay burnt out and I didn't know it...bad relay).

JWMotorsports: do you know if the Red Line Water Wetter effects the freeze point of the coolant at all?

damn i was getting nervous at 210*, 240* seems very hot.

it's mostly all been said; coolant back-flush, oil flush, the rad cap, wetter, lucas..

Then... just for caustion sake... dual Low-Profile cooling fans wired to run 1 all the time and the other to the thermalsensor...<---My plan

Well good new's is I tried the flush and that seemed to work now it never go's over 210 now, and verys between 180 and 210. I think coolant was running low causing it to not circulate through the system at time's. funny problem , but fixed now! fixed 2 other problems also , BOV was open under part boost causing it to over fuel tightened the ajestment screw and fixed that, and fixed another problem with the Low fuel light being on all the time (dim), and then get light once it actually get low . that turned out to be the wire i used, or tapped into for my pod gauges . only reason i mention this is For Bocheck as i remember him have the same problem. just connect you gauges to a different positive power source and that should do it.

i dont think i got anything taped into that wire, alotho il check, so im assuming its a ground switched light then.

Bochek