custom HPS supercharged C43 AMG how to details etc. blown head gasket?

I primarily post about riding here. All this energy that now goes into riding previously went into customizing cars (well, after it all went into ski racing and golf).

I have a 1999 C43 AMG that is a holdover from those days and which I intend to keep for a long time. It has a decent amount of miles on it and has been modified from stock, so isn't in any way what most would consider a collectable. Of course, most people don't actually want to drive their collectables all over the place either. I love high performing sedans, particularly those from the past before every manufacturer jumped on the bandwagon and they got all watered down, and love German cars. Anyways, my particular car has a fairly custom supercharger setup on it and produces something north of 400 hp with even higher torque #s throughout the powerband. No exact numbers right now (it hasn't been dyno'd since the latest modifications, but it pulls pretty hard) I used an "off the shelf" HPS supercharger kit initially, but now the only stock parts of that kit are the Eaton MP90 supercharger, the supercharger brackets and the rising rate fuel pressure regulator. I'm briefly going to list the other parts that I used because a lot of people ask "what it took to make that kit work"...

Necessary stuff-

larger fuel pump- stock pump didn't keep up well enough, I would get the "044"or whatever Bosch one. Mine is a pierburg that came as an auxiliary inline pump for a Camaro supercharger kit.

splitsecond MAF scaler- or some other way to adjust the signal the ECU gets from the MAF. You have to "smooth" it and keep the total value under 4.9v or else you'll get choppy throttle response and other issues.

rework the air intake to use a larger filter and locate it where it gets cool air (this may not be NECESSARY, but it's a real good idea)

be sure to get excellent vacuum source to the fuel pressure regulator

other stuff-

larger fuel line
methanol injection
air-water intercooler system- uses cobra mustang parts and an "ebay" intercooler core
single electrode copper plugs
added a switch to "fully" turn off the tcs system- prevents a lot of potential bad things
polished upper intake
full suite of gauges
lots of under the hood powdercoating

I may be missing some things that I did as it has been about 4 years since I did all the work. Feel free to ask me about it if you have questions

here is an old picture-

Now, while this ran very well and strongly over the past 3.5 years since being supercharged I believe I have now blown the headgasket! I'm no expert on broken stuff (never worked as a repair mechanic or dealt with a blown headgasket) but it seems that is the most likely problem


loss of coolant and coolant overflow after use
white smoke
clear/white gel in coolant

Initially, I spoke to a Mercedes mechanic friend about the issues and he suggested I replace the thermostat, coolant cap and radiator. I do have those parts here now-

I also have new front brakes (this is a 16oz beer can btw), which I've been holding off on installing until I sort this out-

Today I started tearing stuff apart and for the first time was able to confirm/see the presence of the white/clear gel in the coolant. I also ran the car some before beginning to tear things down and did observe white smoke, although fairly subtle.

I drained and removed the radiator and pulled the AC condensor (I plan to pull the AC system permanently)

I pulled one of the easy to reach spark plugs-

checked the oil cap-

I also pulled the dipstick and looked at the oil/quick checked it for water (dropped it on hot surface to see if it boiled). It smoked rather than hissed/boiled etc., and looked fairly clean-

At this point it seems pretty likely that the headgasket is the problem and I have decided not to continue with the repairs until I can absolutely rule it out or fix it.

Due to the modifications to my car it will be a huge pain in the ass to do a cylinder by cylinder compression test, but that may be what needs to happen.

I wonder if having my oil analyzed wouldn't "prove" the headgasket is the issue, or if I shouldn't just consider it already proven.

If the headgasket is the problem I will most likely have to buy a new motor and swap it in. I believe the labor involved in changing the headgasket would not be worth it vs. the cost/labor involved in an engine swap. I guess it will give me and excuse to make my car a C50 or C55 (by adding a larger displacement motor).


Here is a picture of the peaceful snowfall which co-conspired with the stitches in my leg to keep me off of my bike long enough to work on the car and type this up today.

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