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Few weeks ago I got a Check Coolant light....it was low, coolant was on the floor. So, play around, get a whole new tank (the other one was old). Same issue. Well, get a new cap. Seemed to have fixed the issue.
Today "check coolant" is on (starting the car). Signs of coolant on the tank, and under the engine cover......what y'all think I should check next?
The car is in right now getting pressure tested. This, days after the other thread about replacing the pump and all plastic hoses on the cooling system...I am due.
Ol'Man, do you see evidence of your TT coolant overflowing??
overflowing top cap... fir some reason
That right here looks like how circuit got empties.
I wouldn't go look for an additional leak besides that one...
perhaps the tank cap was loose...
perhaps engine turbos got too hot...
perhaps traffic jam was too long...
Do you think better pistons heat removal from combustion could positively help the turbo heat removal as well??
+++ connected ...
one thing we know is the turbo oil pump & engine pump are connected and pump the same oil... meaning engine oil temp affects turbo oil temp.
Last edited by CaliBenzDriver; Oct 3, 2024 at 04:23 PM.
You went out on a civilized normal drive around town then found coolant on the floor.
You idea of "clogged turbo cooling line" links to limited heat removal... ie. too much heat!
-- Are both caps spec'ed with identical pressure relief or different value ?
I could be wrong here... but that is starting to sound like "extreme heatsoak" after the engine stopped.
The pistons heat transfers in to the heads And into turbos - At that point... the uncirculated oil can not help removed heat - It all gets transferred into coolant.
My little poney lacks turbo but had been leaking coolant since new during "extreme heatsoaks" after returning home - This was caused and likely for you as well by dry pistons accumulating heat at normal driving RPM under MOD-0;1.
Meaning marginal oiling overheats coolant to remove uncontrolled heat.
My coolant no longer spills driving in 102°F summer weather. Perhaps this can benefit your use case.
Last edited by CaliBenzDriver; Oct 3, 2024 at 05:15 PM.
> What oil are you running....
oil grade links to spray RPM and cooling effectiveness.
If you are comfortable only with "MB Approved" lubricant (sleeveless aluminum cylinders) - You can trst drive RPM up to 2500 to have enough pressure to spray-cool pistons without using higher grade 15w40/5w50 exotic SP oils.
No problem... MOD-1 gives your engine as much pressure as the oil pump builds up for a given RPM.
Higher viscosity > more pressure > spray at lower RPM: no accumulated heat at driving RPM.
Unnecessary coolant heatsoak leaks cancelled 👏
It's a poor setup for luxury cars to boilover coolant and vaporize oil to "save gas".
We are currently fixing to test a small increment to 5w50... you can eye jumping ahead to experiment 10w50 (TT in a warm locale)... or better: go up grade step step to clean up dirty rings.
HEAT is the reason your engine in boiling coolant...
Last edited by CaliBenzDriver; Oct 3, 2024 at 08:24 PM.
Well that's a good oil to "save gas" but then note how the savings are spent in repairs...
Being an early MOD adopter, what did you make of the opportunity to better lube your engine??
A 5w30 lubricant shears in the W20 range - Get used oil analysis as needed.
Using 5w30 grade is 95% the likely cause of your engine turbo over heating itself.
Turbo service life benefits from effective cooling even more so than cylinders.
Drain that oil ASAP at your convenience to switch to a better oil grade in the W40 range.
Last edited by CaliBenzDriver; Oct 3, 2024 at 11:11 PM.
I am not sure if it is a consideration, especially after a definitive reply about oil viscosity being the likely culprit. However, if there is a residual heat warning, engaging the residual heat mode will cool hot spots after the engine is turned off. Every time I get that warning, I engage the residual heat mode, and make sure my trickle charger is plugged in.
Two things - as for Oil, I have 5-40, not 5-30 in the car....
As for the the coolant. The shop ran a diag on the car. Computer plugged in, it auto bleeds the coolant. I guess it even controls turning on the heater, defroster and holding the engine @ 2200rpm for 20 minutes or so. They say I had a bubble in the system....
Now, it is wait and watch for the next day or so. Being as the car is at 60k/mi I am going to order all of the coolant hoses as per the very helpful (other) thread and replace things (time to play parts canon!!!!)
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by OldManAndHisCar
Two things - as for Oil, I have 5-40, not 5-30 in the car....
As for the the coolant. The shop ran a diag on the car. Computer plugged in, it auto bleeds the coolant. I guess it even controls turning on the heater, defroster and holding the engine @ 2200rpm for 20 minutes or so. They say I had a bubble in the system....
Now, it is wait and watch for the next day or so. Being as the car is at 60k/mi I am going to order all of the coolant hoses as per the very helpful (other) thread and replace things (time to play parts canon!!!!)
1. Which coolant circuit? Engine or turbo? Your pics look like the turbo circuit.
2. The turbo coolant circuit does not circulate through the heater core.
3. I did not know there was an auto-bleed function. XENTRY makes no mention of it. XENTRY only shows a pneumatic method of bleeding the engine coolant. What diagnostic computer did they use?
3. I did not know there was an auto-bleed function. XENTRY makes no mention of it. XENTRY only shows a pneumatic method of bleeding the engine coolant. What diagnostic computer did they use?
I need to do some research on this.
I will ask them. The "Mercedes" guy is (was) a Mercedes Master Mechanic at a semi-local dealership until recently. They had two caps, one for each of the tanks. Caps connected to a system (vacuum?). Was was not there to see the system controlling the cars AC systems (I was told this happens).
To that...they did all of the work for no charge. They said that they were excited to test out the new system with a customer who would understand if some other thing was found. Its a car, they break, I get it fixed....all with out yelling at mechanics :-)
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
The method for bleeding the coolant system in the WIS is the vacuum method. First, drain all the coolant out of the coolant system. Then attach the vacuum device which is usually powered by an air compressor. Hoses will collapse in the process. When all of the air has been sucked out, it is a good time to see if there is a leak or not by watching the vacuum gauge for movement. If it holds vacuum, you attach a source of coolant (5-gallon bucket from Home Depot) and let the vacuum suck the coolant back in. When the vacuum gauge shows 0 vacuum, you're done.
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