Semtex

I am losing coolant at about 1/3 gallon every 1.5-2 weeks w/ stage 1 Renntech tune and pulley. I have had a pressure check done, no leaks. I have had the glycol test done and it was negative. The dealership is telling me that the tuning makes the car run hotter and the coolant is evaporating? The car runs right around 100 so that does not make sense to me either? I have been cutting the coolant w/ distilled water and that has not really changed the loss rate. Does anyone have any other ideas. I am getting tired of putting coolant in this damn thing! Thanks for anyone that has any ideas. Oh yeah it is a 2003, Renntech and pulley are only mods.

StephenK

Sounds like more Renntech BS. Call them and get them to get to the bottom of it. Hopefully they will not blow you off.

Bif powell

Could this be the inter-cooler dumping coolant into the intakes?...I think that's the standard diagnosis when you're loosing coolant like mad (can't imagine that quantity it making into the tranny, but with the W203 all things are possible.

https://mbworld.org/forums/showthrea...nt#post1584665

jgsx

I doubt that it is related to your pulley upgrade.

M5CLK

I dobut it's your upgrades too, mine's stock and I'm losing coolant as well and pressure test and intercooler core were clean... I think someone suggested I might have air trapped inside, and that's the only logical answer for now, but I'm pretty sure my shop did bleed the system the last time, oh well, I guess I'll just have to wait couple more months to see...

Eurocharged Rick

it has nothing to do with your Renntech upgrade...have your intercooler checked by pulling one of the surge tanks...

reference this thread, post #41 for pictures

https://mbworld.org/forums/showthrea...cooler+leaking

Semtex

Thanks for all the inputs. I am going to take a look around the engine this weekend when I have some time. By the way does anyone have a cooling system diagram? If it is just a search thing let me know as well. Keep any other ideas coming (especially ones that don't rhyme with $1200 intercooler that no one has in the states!)

Eurocharged Rick

http://www.c32life.com/intercooler.jpg

CynCarvin32

I did not gather that RENNtech felt the car was burning coolant. Coolant is never burnt off unless you are over heating and coolant is boiling out of the system.

No one at RENNtech would make a claim like that. And actually Hartmut at RENNtech was the only guy around who knew about intercoolers leaking 3 years ago when the parts starting failing. After having a C32 that was drinking coolant just like the car in question Hartmut said take the intake runners off and look down into the runners and look for dried up crusty yellow gook everywhere. When I did, the car had the airways 1/2 blocked with ages of dried coolant that was being injected into the motor through a leaking intercooler core. When the car is shut off the cooling system is still pressurized and the coolant leaks out though broken veins in the core and slowing drips out. It can then cake up on the core or be dripped or blow into the intake runners and dry there. The leaking during driving is mostly burnt in the motor bit it to can be seen in the runners as it collects with time.

From what I heard the intercoolers had be failing in europe long before they started showing up here in the states because the cars because the core was so caked in coolant that it was not cooling very efficiently (limited airflow over the core) and prolonged high load driving (like in germany) make the issue known more quickly.

If the car in question is not showing a leak anyplace else (like in the tranny or from a leak through the coolant pump, it likely is being leaked into the motor and being burned up in the motor.

It is best to get the issue resolved since coolant in the motor can lead to fouled up 02 sensors and damaged cats.

Semtex

Thanks for the diagram 1FastC32

Semtex

Also if I find the expensive green slime how should one go about cleaning it??? Hoping for the best expecting the worst.

Eurocharged Rick

a Dremel with a carbide bit...

Semtex

I searched but could not find if there is a gasket associated with removing the surge tanks? Anyone who knows could you help me out? I want to tear down the surge tank this weekend. Thanks

Eurocharged Rick

there is a gasket, the only place you can get it from is the dealer...BUT:

1. if you are careful, you may not need to replace it, but i would plan on it just to be on the safe side...

2. the other option is to plan to use a very small bead of gasket maker to go on top of the gasket inorder to seal it back up...but i would not recommend this option unless the gasket is not sealing to begin with...

Semtex

I traced the entire "visible" coolant system today and found no leaks. There was some corrosion on the two lines that come into the back of the right side of the radiator. I am not sure but they appeared to be part of the HVAC system?? I have a gasket on order for the surge tank so when it comes in I will peel it open. Does anyone know if there is a digital factory manual on line some where? Preferably in English. It has been years since I have read German or tried to convert NM into Ft Lbs. Thanks in advance.

Eurocharged Rick

the only thing that i know of online is alldatadiy.com

Bif powell

Alldatadiy has been more or less helpful for me - at least it has paid for itself, but it has it's sucky side. Once you figure out how to get decent diagrams out of it, it's not too bad.

Semtex

I have new hope for those of you who have had mystery coolant loss. The first element in this epiphany is that my service manager took it as a personal vendetta to solve this problem. He was pretty embarassed that they could not diagnose the problem and we had a brain storming session. They always tested the system with the vehicle hot and pressurized. This led to the faulty "no leaks noted" result. Turns out my car is having an awful time with temperature changes. (see my write up on the windows not working in the morning for more details) Turns out it was the "intermediate line" going into the bottom of the radiator. It is a partially steel and partially rubber line that the junctions between the steel and rubber leak after the vehicle cools. Since the rubber and steel contract at different rates it wore a small crack into the rubber portion at the junction. This crack is only visible when the lines are cool since when the car is hot both the steel and rubber expand sealing the crack and subsequently allowing the system to "pass" the leak test. It is a $300 part/labor item but far more economical then a $1400 intercooler. Just for giggles he pulled the surge tanks and verified there was not also an intercooler leak. Total bill for solving this little dilemma of mine...$300 parts and labor. There are still a few honest brokers out there you just have to find them. Hope this becomes more of your problems rather than the intercooler. Thanks to all that replied and offered assistance, I hope this helps someone in the future.