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S600 and Engine Heat.

7K views 37 replies 8 participants last post by  cowboyt 
#1 ·
Has anyone fitted S600 with extra fans? Or Vents to relieve excess heat from the engine bay, which is responsible for most mechanical failures? Looking at fenders and high flow Front Spoilers. Any thoughts would be excellent.
 
#3 ·
Looked to be about 90




Today the temp Read 83F outside but it was really 78F. The car was running at 85-90F all day.

But I'm reading that S600 has a problem heat and shaking. The excessive shaking and high heat will decline the engines reliability. So I'm wondering can I use a few approaches to help the engine heat transfer more effectively and efficiently.
 
#5 ·
I have thoroughly searched these forums both before the post I've made and second throughout the answers I receive.

A few Mercedes techs have discussed with me, that heat, and volatile engine movement such as shaking from misfires and bouncing from bad engine mounts will lead to engine reliability problems.

Maybe someone has been proactive, Recently!!! As id like to keep My S600, and 750IL on the roads, making them as reliable as humanly possible, because S500 and 750li while they are great cars to me, I still prefer my V12s on the road.
 
#6 · (Edited)
Hi,

What you're mechanics are saying doesn't really tell the whole story here, yes Vibrations and Misfires will cause heaps of problems BUT .........

What they haven't said is that because these cars are now getting older and available cheaper to purchase, they are falling into the hands of the guys who will ignore vibrations, drive the car whilst misfiring etc etc, mainly because they either can't afford to fix the problem, or are of the "fix it when it stops" mentality :wink

V12's shouldn't shake or vibrate..........

Remember, they are cheaper because of the higher running costs, but a well maintained example is a fantastic car for the money, provided you keep it up to scratch

So does it misfire and are the engine mounts old or u/s ????
If so, sort the issue.

Your coolant temps are fine, exactly as they should be.

Yes these cars develop a ton of under bonnet heat after a thrash on a hot day, but that tends to build up as you stop, because then there is no airflow :wink

It is always good practice to leave a car idling for 5 minutes, or open the hood for 10 minutes after a thrash on a hot day, especially turboed motors

That is why Mercedes spent buckets of money developing these cars............
They put heat shields around everything, and cooling ducts beneath the car in the under trays...........

Are all these parts still in place ????

One of the things that really winds me up is when "Oiky Shade Tree Mechanic" decides to leave these parts off :laugh left on the scrap pile of his workshop, because he obviously knows better than Development Engineers with the huge budgets :frown

I have several customers with V12's, they have 100k ish miles on them, and whilst they can be more "fussy" than the V8 cars, I wouldn't say they are unreliable due to heat soak, and they don't shake and vibrate :wink

HTH

Cheers Dave
 
#8 ·
Hmmm. To sit on my hands or not......

I happen to think that a lot of V12TT problems are caused by that oven of an engine compartment. The cooling systems themselves are adequate (and must be properly maintained to keep them that way) but the physical properties of the plastic and rubber parts around the engine do seem to suffer from the heat once it gets over 200F for any length of time. Metal parts are much more robust, even copper and aluminium.

The thing with thermal management is that you have to consider different heating and cooling mechanisms. The coil packs overheat for example. There's not a lot that can be done about that, as the coils themselves just don't have enough space, but we should avoid using V12NA spark plugs with 1.0mm gap. Mercedes did add heat shields to the coil packs, but they're screwed against the coil pack covers, and provide some IR reflection against the turbos, and some additional thermal insulation from the ambient air. However, they not very good at keeping the equilibrium temperature down, because there's no good mechanism to remove heat, and achieve stability. Having air gaps on both sides of the heat shields is effective, but stock shields don't.

I made some new shields for my car, made from a single sheet of aluminium, and with a gap between the shield and the coil pack. I did a before and after test using temp sensitive tape, and I measured a temp drop of 10 F with the new shields. Whether that actually improves reliability I couldn't say, but the coil packs need all the help they can get, and I think it showed the stock shields left something to be desired.

Another common weakness of the V12TT in general is the ABC suspension. There are about two dozen flexible high-pressure hoses, and the ones that fail most frequently are in the engine compartment. Mercedes do fit heat shield sleeves to a couple of ABC pipes near the exhaust cats, and they're very effective. However, I think ALL the flexible ABC hoses near the engine should be protected, so I added fire sleeve to all of mine. This works well because the ABC pipes cool themselves through fluid flow, and you just have to SLOW DOWN the heating. I think this is a really worthwhile measure, and everyone should do it.

The charge cooler system is effective when it's working properly, but the installation leaves a lot to be desired. Quite a few people have re-routed the intercooler water feed and return pipes away from the exhaust manifolds, which sounds sensible. I actually added aluminized fibreglass insulation to my pipes, though I wouldn't recommend it to others. They're a pain to fit, as is insulation to the intercoolers themselves.

Nick


http://i270.photobucket.com/albums/jj89/welwynnick/IMAG1031_zpsm4kf3xe2.jpg

http://i270.photobucket.com/albums/...5-fa8a-4d94-b7b1-ddef5d84a7cf_zpsfd082764.jpg

http://i270.photobucket.com/albums/jj89/welwynnick/IMAG1093_zps13623ff4.jpg

http://i270.photobucket.com/albums/jj89/welwynnick/IMAG1085_zps88e8695f.jpg
 
#9 ·
I know everyone likes to think Mercedes engineers have done everything right from the factory but as I watch New and used cars flow throw the auction blocks with each automotive manufacturers prone defects, I can assure you, they haven't.


What I was simply asking above, which Nick surely has pointed out, is that there is a problem in that oven. V12 NA has an oil cooler attached to that Oven. V12 TT was a total redesign and in my opinion "admission" that "hey we messed up, so let's make them happy".

while I have been compiling data on this car, so that my W221 S600, and W222 S600 experience are a joy as well, the Mechanics at my local Mercedes have been more than willing to share a wealth of knowledge with me. As per the 4 I've talked to, Heat transfer is the issue.

Dave discussed above about opening the Bonnet on an exciting Day of driving, if you do that, you will definitely feel the fire lol.

My S600, is not electronically limited, and is running the Renntech Program. It with spin the wheels without hesitation, I know with that force, comes heat.

It sounds like Nick is saying rather than trying to find ways to release it, we should increase protections on the parts already protected. That gives me a new way to look at the problem.

Thankyou both, Nick I'll take a look at what you've presented tonight and see how to apply that method to what I'm thinking. I ultimately wanted to increase air flow, but I think a combo of the two will be perfection.
 
#10 ·
And Nick, a Hydraulic Shop has confirmed to me that these Contitech hoses are of the lowest technical spec we have available right now.

They have removed that rubber section for me and I will post some pics in my Suspension thread.
 
#11 ·
Put in some fender vents

That's what lorinser did .

There are less garish ones available


Yes there is a definite issue with underhood Temps on a v12. No other car I've seen generates so much underhood heat. Even if the cooling system is keeping the engine internals within spec , the underhood heat in a 600 is way more then a 500. Heat destroys electronics , plastic and rubber components
 
#12 ·
Love the idea




Will the fender vents help heat escape directly out the engine bay? I know exactly which vents you are talking about. they run along side the wheel arches. My point exactly about that Heat scenario. That Electronic box attached to the center of the engine will get blazing hot. On a hot summer day.
 
#14 · (Edited)
This is an excellent way of getting rid of excess heat, however, take a look at the pic below, (W220 with Fender removed) ..........

I fail to see how one could get even a 4" metal flexi duct through the inner wing / chassis and behind the Plastic Wheel Arch Liner without some serious structural modification :confused:

Without having ducting, and an inline blower fan, vents in the fender would be nothing more than cosmetic.

Does anyone have pics of how Lorinser did this, as I am intrigued ??

Cheers Dave

Pic .......
 

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#22 · (Edited)
Hi,

Nah, sorry but I'm not convinced that is anything more than cosmetic..........

It enters behind the wing into a sealed area, and like my earlier picture with no fender shows, you'd have to cut away Chassis and Inner Wing areas to get a duct through, thus seriously weakening the front end of the car.

I have proved categorically that all hood vents do is allow rainwater to get all over various engine components, to detrimental effect. The SL's sure look cool with those vents, so did my 1996 Firebird V8, but they are nowt more than cosmetic.
They only allow residual heat to vent out when the car is stopped :wink

As for cutting holes in stuff, my Special Stage Rally Car has a tiny Engine Bay with a V6 24V Cosworth motor and 4WD running gear squeezed in, and a 10mm Durally full length sump guard underneath.........

That never overheated, but would try to vapourize the skin off your face at the end of a 30 mile stage, when opening the bonnet to let out excess heat / check........

So I tried all sorts of vents, ducting with fans etc, and used IR to monitor under hood temps in different locations, all the vents etc that I tried had various negatives, in the end I fitted a stock bonnet back on it and left it as it was.

This car was scratch built by me from a bare Ford Puma Shell, and has proved to be very competitive.

In 5 years of hard competition use, it has burnt out 1 coil pack, but that was probably just coincidence :wink

The best way to prevent a lot of under bonnet heat is thermal exhaust wrap for headers and downpipes / cats, this also makes Turbos more efficient :wink

Cheers Dave

pics.......
 

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#16 · (Edited)
Not being overly-hampered by facts, I can discuss the subject freely...

The primary heat-removal method for the engine compartment is air flow thru the compartment. If you install any exit vents in the forward part of the compartment, you will reduce the air flow in the rear of the compartment, increasing heat build-up in that area. The best place for hot air extraction is at the rear of the compartment, preferably at the bottom of the car. You want to "wash" the entire engine with air.

I have speculated about a small "spoiler" installed on the back/bottom of the bottom engine covers to create a low-pressure extraction area area at the back of the covers. Perhaps a piece of flexible lawn edging...
 
#17 ·
Yes the reason I asked is because I've seen a model showing how Air is pushed through the front air Dam and out the fender vents really for Areodynamics rather than cooling.but I like the Idea of moding the liner to allow heat to be removed. Also the cooling fan will have less work to do.


It's like a Catch 22, we want the engine to heat up to op temps as fast as possible, and then find ways to remove as much of that as possible
 
#21 · (Edited)
Let's not forget that heat rises . Putting cooling vents only at the rear bottom of the engine do nothing about all that heat trapped right under the hood , where the voltage transformer and coils reside . That's the problem area .

I think it is best to have a way for air to wash across the upper part of the engine compartment . As currently designed by mb, the upper part of the engine is fairly tightly sealed with no place for the hot air to go.

The sl65 black series had massive hood vents .



 
#23 ·
"Wally you want a spoiler to push air up into the back Of the bay?"

No - the spoiler would be attached at/near the rear of the lower engine covers, on the bottom of the cover. The idea is to create a low-pressure area at the rear opening of the covers, so as to increase air flow thru the engine compartment. You probably wouldn't want the spoiler to be more than an inch or so in height (lowth?)

Man, Dave! You have some nice toys!

One of the first times that I realized that air flow isn't simple was when I discovered that the cute little air outlet vents that the factory installed on the MGA 1600 actually pushed air into the engine compartment, and increased under-bonnet temps. The high-pressure areas on the hood/bonnet start a lot further forward than most people realize.

I also agree that getting any significant out-flow thru fender gills is harder than you might think.

Automotive airflow is a complex black art...
 
#24 ·
Standing still, at outside temperatures ranging between 15 Celsius and 32 Celsius, my S600 TT (2003) goes no higher than 95 Celsius on the dial. At highway speeds, that temperature goes down to 80 Celsius.

This was confirmed on a recent road trip, with the air conditioner on at outside temperatures above 27 Celsius. There were a few times I got into the throttle, sure, but I generally drove it "normally", i. e. not lead-footing it.
 
#26 ·
And this causes Problems




I've seen the Box on top of engine with circuits in Pieces. There is no way this baby can last effectively being subjected to the high thermal temps in that oven. Another reason I think the coils are prone to failure.

Coolant temps don't tell The whole story.
 
#30 · (Edited)
Thank You Guys,

:beerchugr:

That is exactly what I found with the Stage Rally Car..........

That "searing, face peeling heat" that we feel when opening the bonnet, (hood), on a hot day is simply heat from a red hot, roasty toasty exhaust rising up and exiting the now huge open aperture.

This then leads all sorts of "Mechanics" to start all this "folk lore" malarky :wink

Thermal Exhaust Wrap helps no end with this, and we do this on all the rally cars now :wink

"Here endeth the first lesson" ...........

If it ain't broke don't fix it :grin

Cheers Dave
 
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#31 ·
Dave I just got back from a 800 mile round trip:

Engine is a V12 NA - Renntech Program. Miles are 141,000

Had I seen your test, I would have performed it while on the trip, but I will absolutely perform it in the next few days.


You're essentially saying the heat rises out the bonnet once it's lifted because it has a new way to escape.

I don't think 10 minutes of thrashing is a legible test. More like a "stop and go traffic on a hot summer day with no way to escape and the only cooler is the electronic fan.
 
#33 · (Edited)
Hi guys,

@ nrphily,

Yep, excellent please post up the results I'm keen to see them, and hoping they agree with the "normal" findings from all the testing done by myself and others on different High Performance cars.
I agree, the longer / more testing will give a better spectrum for data analysis

After I posted yesterday, I was thinking back to my teenage / 20's years when we had Jaguars........ XJ,s and E Types etc, with V12's and how they used to "peel your face" when you opened the hoods on a summer day :grin
And believe me that was long before Electronic Fuel Injection, my first V12 had 4 big Stromberg Carbs :laugh

@ cowboyt

Yep, that says it in a nutshell, very eloquently put......
And yep changing that set of plugs avoided unduly stressing the Coil Packs.

Regards thermal exhaust wrap, it will be an absolute bitch to do properly on a V12, may even require removing the engine..........If you decide to do this, also take a look at having manifolds etc ceramic coated, I've heard that works well too...........
If you have a Turbo motor, you can see the results of Thermal Efficiency on a dyno, and can certainly feel the difference driving the cars :smile

As you rightly say, proper maintenance is the key here, it is just a shame that a hell of a lot of "Professional" Garages are charging car owners for items, and either they don't need all the items or they are not actually fitting these parts. Trouble is it is soooooo difficult over here in the UK to actually get anything done about this.

I have seen it many times, over my 40 odd years in this trade and it just "tars" all Workshops "with the same brush" :frown

I guess, if you've got a good Indie, stick with him, a lot of Main Dealers seem to be the worst, and not just MB, I've only really gotten heavily into Mercedes over the last few years !!

Cheers Dave
 
#34 · (Edited)
#36 · (Edited)
PMercury has installed hood vents similar to the sl black series on his cl600

https://mbworld.org/forums/cl-class-w215/667148-another-best-cooling-mod.html
Quote cowboyt :-

Hmm...that voltage transformer positioning looks interesting and doable, but I wonder about the scoops in the hood/bonnet. When it rains, water will go right through those vents and straight onto the engine. Is that really a good idea?

Hi,

See my post #22

If you look closely at those "vents" they look to me to be sealed on the lower edges, i.e. they are just for cosmetic purposes, and they merely collect rainwater :wink

Yeah, on 3 cars that I've had with vents which go right through, parts have always got wet / damaged by water ingress.

Regards moving the Transformer, what is the method and equipment used to calculate a 150 degree drop in temperature ??

I'm not doubting what tusabes is saying, just maybe he's got the info somewhere else, rather than first hand..........
From the research I did, (admittedly not on a V12 Mercedes), that end / height of the engine bays was the hottest !!

I used IR heat sensing equipment and software.
This gear was used by London Underground Fire Protection Engineers in simulated fire experiments to determine where Alarm and Extinguishing equipment would be best placed :wink

Cheers for now,

Dave
 
#35 ·
Hmm...that voltage transformer positioning looks interesting and doable, but I wonder about the scoops in the hood/bonnet. When it rains, water will go right through those vents and straight onto the engine. Is that really a good idea?
 
#38 ·
It does appear to be a sound method of measurement, looking at those pictures. Even if the temperatures are off by, say, 20 degrees, the delta is still pretty impressive.

It also helps that he installed an ice-water cooler ("Killer Chiller", I believe) in his car to help keep those temperatures down. Given the temperatures in Bangkok, Thailand, I'm sure this does help some. Banks Power installed something similar in their Dodge Dakota "Sidewinder" Diesel pickup truck, and apparently those things work well.
 
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