Oil cooler diverter valve

[shimmy]

Originally Posted by The Gorilla

Hi,

Shimmy- in regard to the ''running hot'' which
if I am correct was at Spa ? where cars with
almost identical set ups, in respect of Cooling,
was that some Cars after several laps and with
ambient Air Temps being above 28c ?after
several laps with high engine loads, some
cars were OK on water temp, although they
were experincing higher oil temps, but your
car and a few others ? were seeing very high
water temps and having to lift, ie reduce load
to cool engine water temps down.

I think there was another thread where somebody
was running their Heater on full to try and
pull temps back down

For sure front number plate removed, AC Rad etc
removed could all assist and might make a few degrees
difference to overall coolant temps but not the
differincies you talk about.

From what you have said I would guess that there was
a good 10 maybe 15 degree difference in coolant temps
between almost identical cars [cooling set up etc].

Based on what you have said and if I have read it
correctly in regard of the overall conditions and symptons,
then this may well be Anti Freeze related.

Example- A pressurised coolant system with 30% anti freeze to 70%
water will start to boil at least 12 degrees lower than the
same coolant system with 50% anti freeze 50% water.
The same coolant system running 70% anti freeze with
30% water, the highest mix you can run, will run well over
15 degrees more, even higher in some conditions.

While nobody knows what percentage Anti freeze the various
Cars were running, it is a fact that its the water system that
cools the thermal store [engine] so the more the water temp
rises the less effective the coolant is being, which can only be
down cooling of the rads etc or the coolant itself.

As the cars mentioned were all almost identical with same water Rad,
oil rads, std hoses etc and the fact that number plate and A/C removal
might make a few degrees difference then it does suggest
that the reason may be some cars could well have been running a much higher
concentration of Anti freeze thus running at approx 10 maybe 15
degrees lower on the water Temp Gauge, but still showing similar
higher oil temps.

If it was down to cooling air flow then there would have to
some major differincies between the cars in question
which from all accounts there is not.

Bit off topic but still related, just.

Regards,

The Gorilla.

I take your point on antifreeze although US car in California have same issues and I doubt they run any antifreeze (but worth a shot)

Basically ANY track with decent straights (100% throttle areas) after a few laps pushing on (and I push pretty hard) after getting up to temperature, after a distance at 100% throttle you see the oil temps again starting to rise first, not much but a rise, followed by water which starts to rise form just under 3/4 to the red (obviously you don't let it go to the red)

Once you hit a few corners or if you back off, the car cools back to normal quickly.

Tried changing rad(cleaned and flushed), oil cooler(new), MStat, new water pump, new viscous fan, new fuel regulator (as they can make car fun very slightly lean), new fuel filter, also obviously had new engine which rules that out.

I thought the symptoms where feeling related due to the 100% throttle issue, but now I'm thinking maybe is air flow and somehow at high speeds the air (entering already at 23-24oC air temps doesn't cool the engine at 100% throttle

BUT I am seeing the oil rise first, not water....does that make any difference to what could be the cause?

[northernjim]

Originally Posted by shimmy

I thought the symptoms where feeling related due to the 100% throttle issue, but now I'm thinking maybe is air flow and somehow at high speeds the air (entering already at 23-24oC air temps doesn't cool the engine at 100% throttle

BUT I am seeing the oil rise first, not water....does that make any difference to what could be the cause?

I'm not saying you're big boned Shimmy but....







maybe there is another reason the little donkey overheats in your car?

[Mike R]

Shimmy,
Have you tested the coolant for any signs of hydrocarbons? The symptoms you describe are classic head gasket failure?

[AlexGTT]

Originally Posted by shimmy

Lawsy, the heat soak issue will only turn up around 23-24 deg C so you'll have to come south to catch that sort of heat, but very very interested in the results.

The whole airflow issue inc number plate and fans is interesting and worth playing about with (does Alexxgtt run without front plate on track, as he also has experienced the heat soak overheating)

Shim, I run smaller number plate but no number plate holder. The bottom edge of the plate does not impede on opening to lower rad feeds.

My cooling issues were very similar to Shim, only in hot ambient temps and the cars are similar spec.

I now have Turner Motorsport oil cooler and oil temps do not rise like they did. However, water temps did but slower than before.

I would explain the differences some are experiencing is mainly down to driving. You only have to back off a tiny bit to see temps drop back, for example change gear 500rpm sooner. I've sat in many CSL's on TD's and it's quite evident to me how each person uses different revs, short shifts here or there, some are WOT in certain places where others aren't, etc. I'm not saying some are faster or slower, only that some achieve similar lap times but in very different ways.

The problem is obviously: the inability of the cooling system to extract enough temps out of the engine coolant under full load once full heat soak happens in hot ambient temperatures. Simply broken down it's either lack of rad cooling area, lack of sufficient coolant flow (restriction) or a combination of both.

I think it's coolant flow and I have tried something that up to now has worked. However, I'm staying cautious until fully tested at a really hot TD. So far it's worked at a track in 25 degree heat. That same track in identical temps previously caused the issue.

Now waiting for Summer.

[AlexGTT]

Originally Posted by Mike R

Shimmy,
Have you tested the coolant for any signs of hydrocarbons? The symptoms you describe are classic head gasket failure?

No. Shimmy did same with new engine.

Mine is identical and coolant has been tested as well as several leak down and compression tests.

Anyway, besides that, these engines (in the main) only leak between cylinders when head gaskets go and not into water jackets..........unless head cracked.

[The Gorilla]

Hi,

Quote - ''...US car in California have same issues and I doubt they run any antifreeze....''

I doubt they do also but that's the point
as anti freeze has a higher boiling
point than water on its own.

The fact that Oil goes up first and water is
stable, and then water starts to rise will
be caused by the Thermal store [engine]
temps rising beyond the water jacket limits.

In say 28c + ambinet air temp, then the surface
area of the std coolant rad must be almost at the
upper factory limits for the water temp at say 80%
engine load to rise and only fall, when engine load
is decreased.

Hence even a 10 or 15 % increase in airflow, given
the ambinet air temp of 28c +, will do little to lower coolant
temp, either a greater coolant rad surface area so the
coolant limits are increased to dissapte more heat
under high load or the coolant itself must be able
to absorb more heat without boiling.

Think of your central heating system at home
say a 120,000 BTU boiler running say 12 rads putting
out 85,000 BTU, say 14,000 for the hot water cylinder
and it copes to say -8 or 9 now drop the external
temps to say -25 and the 20,000 spare BTU capacity
would be very marginal in maintaing say 75 in the
living rooms and 70 in the bedrooms.

Remove say two rads by shutting down their rad
valves and the overall system gains back say another
10,000 btu's with which to assist in mainting required temps.

I think your correct that in heavy load situations with
higher ambinet temps the std coolant set up breaches
its factory limits, Oil temps start the process by increasing
the thermal mass temps [engine] and then the coolant
starts to struggle keeping within limits.

Its in part why I went with the Heat exchanger and the
Tropical stat as the combination of the two lowers
my normal operating temps on both water and oil
giving a greater margin for when ambinet air temps
are hotter which when combined with a few air
flow alterations and good concertration of Anti freeze
has seen no real coolant issues to date.

Another point on air flow, is that the M3 Alloy lower subframe
Brace and the front undertray prevent any real airflow
around the sump.
Some airflow to the sump would also assist in keeping
oil temps down.

Regards,

The Gorilla.

[AlexGTT]

Originally Posted by The Gorilla

The fact that Oil goes up first and water is
stable, and then water starts to rise will
be caused by the Thermal store [engine]
temps rising beyond the water jacket limits.

In say 28c + ambinet air temp, then the surface
area of the std coolant rad must be almost at the
upper factory limits for the water temp at say 80%
engine load to rise and only fall, when engine load
is decreased.

Hi Gorilla, this is of course the crux of the problem. It is a road car after all and such parameters are not catered for.

[shimmy]

Originally Posted by Mike R

Shimmy,
Have you tested the coolant for any signs of hydrocarbons? The symptoms you describe are classic head gasket failure?

Once again, was first issue but happened before HG failure, after HG failure and after Full engine change.

NEXT

(been through all these)

[shane@mbtech]

Gorilla and Shimmy

Antifreeze/coolant is used to both stop overheating and freezing. Which I'm sure you are well aware Danny.

So yes the Californian cars will run coolant.

The coolant % is an interesting one, and something I will monitor.

[shane@mbtech]

Me and shimmy pretty much same speed at spa, my water temp didn't budge, his moved a lot. It was a hot day circa 28* c iirc.

It's certainly a funny one.

Originally Posted by AlexGTT

Shim, I run smaller number plate but no number plate holder. The bottom edge of the plate does not impede on opening to lower rad feeds.

My cooling issues were very similar to Shim, only in hot ambient temps and the cars are similar spec.

I now have Turner Motorsport oil cooler and oil temps do not rise like they did. However, water temps did but slower than before.

I would explain the differences some are experiencing is mainly down to driving. You only have to back off a tiny bit to see temps drop back, for example change gear 500rpm sooner. I've sat in many CSL's on TD's and it's quite evident to me how each person uses different revs, short shifts here or there, some are WOT in certain places where others aren't, etc. I'm not saying some are faster or slower, only that some achieve similar lap times but in very different ways.

The problem is obviously: the inability of the cooling system to extract enough temps out of the engine coolant under full load once full heat soak happens in hot ambient temperatures. Simply broken down it's either lack of rad cooling area, lack of sufficient coolant flow (restriction) or a combination of both.

I think it's coolant flow and I have tried something that up to now has worked. However, I'm staying cautious until fully tested at a really hot TD. So far it's worked at a track in 25 degree heat. That same track in identical temps previously caused the issue.

Now waiting for Summer.