Overheating

[Boost]

(not EFILive related, sorry, but thanks for your advice anyway)

This is a 2004 LLY - 2wd SB/EC

It has a cold air intake, full exhaust, EGR blocked-off and an Edge programmer.

The truck consistantly overheats when driving. Less so when set back to stock, but still. When I carefully open the coolant cap, it boils over for a few minutes (pressure pushes some coolant out - seems like there is gas or something trying to escape). If the cap is left loose, it never overheats.

It is not loosing coolant and holds 15 psi for 10 minutes. It also passes the block check (chemical does not turn yellow-green). The reservoir is not black. And there isn't any excessive smoke or coolant under the truck.

We already replaced both thermostats and the coolant cap. The water pump seems not to be leaking. The truck has 140k miles on it. What gives?

Help me diagnose this overheating concern please. I thought I understood how the cooling system works on this LLY, but I'm stuck. My first thought was blown head gasket, since the truck is driven hard most of the time. But like I said it passes the block check, weird. Thanks in advance!

[roy]

Afew things come to mind
Does the truck have electric cooling fans and if so, are they turning on when they are suspose too?

Clogged coolant tubes.
Reduced airflow across the fins.

[rcr1978]

Just like Roy said I've seen people use tap water when refilling a cooling system, when using antifreeze that you mix yourself I have seen just after a flush the water can plug of most of the rows with calcium or mineral deposits after a while.

[kodiak]

04 and 05 LLY Duramaxs are notoriously famous for overheating. ANY of the diesel forums will give you all the information you could possibly read.

[killerbee]

Unless it is only overheating when you are pulling a load, ie greater than 80 % throttle for minutes ata time, then you don't likely have the load induced overheat issue common to all LLY's. If you think you do, then THIS ARTICLE (http://members.cox.net/td-eoc/INDUCTION-THERMAL%20FEEDBACK%20PRIMER.doc)will help in understanding it.

http://members.cox.net/td-eoc/INDUCTION-THERMAL%20FEEDBACK%20PRIMER.doc

It is possible to have this thermal feedback issue without a load, if your MAP sensor is bad (melted), but this is not likely.

Also, your post is confusing, if you are not losing coolant, what is your barometer for overheating? Gauges malfunction....etc.

[cmitchell17]

Could the LLY overheat thing cause really slow turbo spool?

My 05 is only making about 7psi by 2nd. It takes it well into second gear to it 20. Thats when the smoke clears then. You can also feel the major lag from a complete stop the tach will just rev to about 3200 and sit there for a second then it will just take off.

Sorry for asking on your thread but I can't get an answer anywhere else.

Anyway my LLY dosent overheat from looking at my dash gauge, but I just got it so I havent even looked at ECT on efilive. Although the only time my fan ever comes on is when you first start the engine cold. But then again I don't do any heavy towing with it.

[Sparky8370]

After you take it for a drive, let it sit overnight with the cap on tight. If there is still pressure in the upper rad hose, than it's most likely a head gasket. I would also check the water pump. Make sure there is nothing blocking the weep hole. Make sure the clutch fan is kicking in when it's hot. Mine is pretty loud when it kicks in, so there is no mistaking it when it kicks in.

[killerbee]

Could the LLY overheat thing cause really slow turbo spool?

My 05 is only making about 7psi by 2nd. It takes it well into second gear to it 20.

Is this with your foot on the floor? Gear is not a factor, load and rpm are.

Without beacoup exhaust gases spinning the turbine, there is no compression. It's a chicken/egg thing.

No, thermal performamce of the vehicle is unrelated to spoolup performance. However, the inherrent restriction in the induction tract IS a big deterrent to launching the egg.

[cmitchell17]

Yes thats at full throttle definately dosent feel like a variable vane turbo. I have read your papers about the intake mouthpiece but can you do everything witout messing up any of the stock intake? How hard is it really to put a new mouthpiece on. Ive never done anything to the truck and want to keep it as stock as possible.

[cmitchell17]

I had a log where I had vane postion and more stuff logged but it got deleted.
But on this one you can see how slow the boost is.

[killerbee]

Ive never done anything to the truck and want to keep it as stock as possible.

Those are the precepts I have designed around. I do no-nonsense, no-bling engineering. It is boring for many, but I like boring. Call me crazy, but I don't like OBD codes.

[killerbee]

I had a log where I had vane postion and more stuff logged but it got deleted.
But on this one you can see how slow the boost is.

Looked at your log, and everything about it looks very typical and normal LLY to me. In fact, MAF is almost too good.

Part of the issue in this log, is that your truck is not warmed up yet.

[cmitchell17]

I wasnt watching ECT. I want to get your intake kit, but are the parts still backordered?

[killerbee]

The modified LLY mouthpiece is available. The IOH is on 30-45 day back order, but if you had ordered it 30 days ago, you'd have it now. This backorder situation may go on for some time.

[killerbee]

It is noteworthy to make mention:

About a year or so ago, Ross worked exhaustively to help me revive some dead tables in the periphery, the less attended tables that nobody pays attention to. That is to say, a few of the them did not work. Once revived, it was possible to use EFILive to diagnose what is known today as "Thermal Feedback" as it applies to overheating under load with variable geometry turbocharging. Those same tables make it possible to stem the effects of thermal feedback, using simple algorithms to limit or reduce boost with the onset of thermal feedback and certain conditions.

I call it "wastegate tuning".

Thank you again Ross, et al. I have a MaxxTorque article in the works that will come out early next year, that chronicles these experiences, and EFILive.

[Boost]

Thank you very much for the helpful advice, and cmitchell I hope you get your truck sorted out.