My LS in normal driving runs at 200 degrees but yesterday when on the highway running between 75 and 80 mph the gauge went up to about 215 degrees. But when I got to my exit (about 15 miles) and was back down to 55 mph it went back to its normal 200 degrees. In my experience with engines that indicates to me that at higher speeds the coolant is going through the radiator too fast to cool. I am going to talk to a tech at the dealership today but would like to know if anyone else has noticed this issue.
Bob

 

Hey Bob,

I agree with you bringing it in to your dealer. Please let me know if you need any assistance.

Deysha

 

Hey Bob, there are a few of us running into high ECTs on the track. I've noticed it's higher on the straights than it is in the slower corners. I attributed that to the WOT condition on the straightaways where the engine builds more heat than the cooling system can dissipate even with the increased airflow. I'm very interested to see what you find. I assume if this were the case, a t-stat with a smaller opening would be the fix?

 

I wish it was this easy too, but I am not sure that it is. The Ford GT's have this same wide-range of operating temperature. They'll cruise on the freeway on a cool day at 165 degrees but the other extreme is hot track conditions where they will be at 215-240 and sometimes unable to continue. Most GT owners have found that the "over-heating" condition is related to RPMs and by managing the revs they can get more laps in before the engine puts itself into limp mode from excessive heat.

There a group of 3 of us with LS's that plan to run at the track this coming Saturday where the temps are anticipated to be 95 degrees. I'll be able to report back our experiences early next week.

 

Yea I talked to David Murray about the GT overheating issue at BIR last year. I was having similar issues with the GT500 and my "fix" was a bigger pulley for the road course. Stiegemeier made an interchangeable hub for me to easily swap bewteen a 2.6 and 2.9. I really didn't expect overheating issues with the NA Boss, which is why I bought it for the track. I too have been managing it (when necessary) by staying up a gear going into certain corners with the Boss where I didn't feel I'd lose much time. I'm just getting on the throttle earlier in those cases to build rpm/torque on corner exit. It's definitely related to revs in the Boss as well from my experience using this technique. It works and drops ECT about 10 degrees. It's just that I'd rather not have to "manage" it if we can "fix" it

 

Unacceptable for you, Gary - you must be allowed to drive flat-out!

 

I think we have a new nickname for cloud9....Flat Out.

 

In both my GT2 and Koenigsegg so I can upload my videos to Twitter for all my fans!

 

You look good on Leno. Looks like you upgraded to a 924.

 

My favorite line of that video..."I am not a student. I have gone 200 miles per hour on the Autobahn in a Caterham.....in the dark......while it was raining"

 

I noticed the same thing soon after I got my LS. I talked to a buddy who is a Ford Engineer about it and he wasn't concerned. Although I would normally take his word on it, I think this is going to become a issue sooner or later.

 

I will say I've run ECTs in the 230s and 240s consistently and the car keeps going and doesn't seem to be pulling back. I've only had it go into limp mode once when it hit 250. That said, I have had to back down from rpms a few times on those days at 90+ ambient. I think if you can keep it under 250 it's fine, but not sure you can do that without some changes on hot days.....

I'm wondering if there's anything else we should be/can monitor other than ECT. Someone mentioned CHT but I'm not sure I can pick that up on my Aeroforce gauge and even if I can, what is the red zone for those temps? I know I need to add a sender if I want to get oil temp.

 

Personally I am more worried about oil temps than water temps. I would think it would give a better indication what is going on in the motor. Since there is a oil cooler, is excessive oil temps causing the water temps to go up?

 

Cloud9 you are correct that at thermostat with a smaller opening would correct the problem I noticed but then you have to take into account that will it slow the water down to a point where it will not cool well at normal speeds. I am a performance engine builder and have done everything from dirt track oval racers to 3500hp Keith Black engines for pulling tractors. On one of the street engines we built a few years ago with a thermostat in place the cooling system could not handle keeping the engine at operating temperature. The sloution cant be done with our cars but we removed the thermostat and replaced it with a restrictor (washer) and after a few attempts found one witht he right size hole that the engine cooled fine. As for running past 220 as an engine builder I would not recommed it as I have seen first hand what damage heat causes (scored cylinder bores, scored piston skirts, cracked heads, taking the temper out of the rings so now you might have oil consumption and the list is endless). On a street car last week I had a guy bring in cylinder heads that I had done a year ago and he thought something was wrong with them as suddenly his car was overheating. I use heat tabs on all my work and if something gets hot (260 degrees) it melts the center out which is what happened in this case. Both heads were warped over 10 thousandths of an inch. The issue I noted may be nothing but as an engine builder I may be overly critical of what I see going on.
Bob

 

This is interesting. I am suspect that the problem lies in the oil cooling rather than water cooling. Is a larger oil cooler available, or does it need to be relocated for increased air flow? It's no wonder they spec a 50 weight oil.

 

Mine was about 198 doing 70 on a trip west a few weeks ago

 

I had issues at PPIR last weekend (96* ambient, 100*+ surface temps) in my boss. Would get about 3-4 laps in before I had to shut it down. Got the red temp light once and popped a little fluid. Strange thing is that it immediately dropped to the 1/2 mark as soon as I hit the pit-in road.

I just drilled out the 200 holes in the fake fog lights to increase the airflow over the upper portion of the radiator.

 

Yea the temps drop quick. I've even gotten away with running up a gear for 3 turns and dropped enough to keep plugging away. Hopefully the holes will help.

If you popped fluid from your reservoir you better pick up a new cap. Unless they've changed them, they're one time use. I got a couple spares from my dealer for a little over $8. Let your car warm up and go listen to the cap....I bet you hear it seeping.

 

The Boss uses a liquid to liquid oil cooler plumbed into the radiator. If the oil cooler is causing the increased coolant temps then adding an auxillary heat exchanger might help?

Either circumvent the radiator part of the cooler completely or plumb the auxillary cooler before the radiator so that it takes some load off the engine's cooling system (keep pressure drop in mind though with the extra cooler and plumbing).

 

So some of you are saying that restricting the coolant flow will help keep coolant temps lower?