Overheating until...

[jbramhall]

I have a 2009 Berkshire 390BH (40) that is behaving strangely.

The engine will run until the dash computer reads coolant temp high and shows an engine temp of 220F. I usually pull over, stop the engine, start it back up, and it would then run the rest of the day with no cooling issues.

On other trips, it was unsafe to pull over immediately, and I drove a bit further, with the temp warning showing in chorus with a check engine light (high 220s F), I assume due to the temp. Stopping and starting again sometimes fixes the problem, otherwise I drive again until the warnings come on, stop and start, and then the cooling system brings the temp in line for the rest of the day.

Here's what I know:

Upon cool start at the beginning of a trip, the fan runs for a minute upon start up then stops,as I think is correct.

The fan is not running when I pull to a stop with the coolant temp high light showing

The fan is running after the pull-over-start-stop rodeo when that sequence leads to proper running temps.

I guess I'm curious if, with the fan running through the 1 minute initialization sequence, does that eliminate the fan clutch as the issue? Must this be a software problem or maybe a lazy thermostat? Can the thermostat be replaced without opening the bedroom engine access panel?

Thanks

JB

[mark0224]

"The fan is not running when I pull to a stop with the coolant temp high light showing"
This would make me think the fan isn't working properly and the shutting off and turning back on causes something to reset. I think I would take to a mechanic before you overheat and do damage to the engine.

[jbramhall]

Thanks, and I'm looking to understand the root condition a bit more.

[VinceU]

Originally Posted by jbramhall

I have a 2009 Berkshire 390BH (40) that is behaving strangely.

The engine will run until the dash computer reads coolant temp high and shows an engine temp of 220F. I usually pull over, stop the engine, start it back up, and it would then run the rest of the day with no cooling issues.

On other trips, it was unsafe to pull over immediately, and I drove a bit further, with the temp warning showing in chorus with a check engine light (high 220s F), I assume due to the temp. Stopping and starting again sometimes fixes the problem, otherwise I drive again until the warnings come on, stop and start, and then the cooling system brings the temp in line for the rest of the day.

Here's what I know:

Upon cool start at the beginning of a trip, the fan runs for a minute upon start up then stops,as I think is correct.

The fan is not running when I pull to a stop with the coolant temp high light showing

The fan is running after the pull-over-start-stop rodeo when that sequence leads to proper running temps.

I guess I'm curious if, with the fan running through the 1 minute initialization sequence, does that eliminate the fan clutch as the issue? Must this be a software problem or maybe a lazy thermostat? Can the thermostat be replaced without opening the bedroom engine access panel?

Thanks

JB

Why not call a Freightliner shop and ask for a mechanic. Discuss the overheat problem and chances are they have heard it before. Maybe you can some help over the phone.

[Ida Ratherbe Camping]

Is your coolant full? Could have an "air pocket" around the sender for the fan and its not reading the high temp. Is there bleed valves on intake or other places on the coolant system? My 2 cents....

[Ida Ratherbe Camping]

Does any of this sound familiar to ya?

2009 ISB 6.7 overheating - iRV2 Forums

[jbramhall]

Originally Posted by Ida Ratherbe Camping

Does any of this sound familiar to ya?



2009 ISB 6.7 overheating - iRV2 Forums

It does seem like a similar issue. The thread there is over 2 years old, but I'd be interested in understanding if the fan clutch replacement was from the top or from the bottom access to the engine. I'm working with a busy local shop, and the complexity will drive the time they need the rig, and, as a result, when I schedule the service. I'm not happy to limp along upon starting out, but I can stop before the temp gets too high and still make some of the trips we have planned in the coming weeks. Pretty much, that was the mechanic's suggestion for now..."Watch the temp and pull off under 230F...come back after Memorial Day when we can fit you in the schedule."

I'm also not convinced it's my fan clutch. The fan does run initially upon start up as if the fan engagement movement works OK, but the logic driving its activation is messed up...as if it doesn't get the message that the engine is hot and it should turn on.

[Still Kickin]

Here is the procedure to check if your clutch fan is operating at proper efficiency. You will need two persons to do this simple check.
Start the engine and observe the clutch fan operating. (it's spinning)
While you are observing the rotating fan, have the second person shut off the engine.
The clutch fan should spin, no more than one to two and a half complete revolutions, before coming to a complete stop.
If your fan continues to free spin for more revolutions than specified, after shut off, your clutch fan is not operating within design perameters, and needs to be replaced.
The fan needs to pull enough air past the radiator to properly cool the coolant when it circulates through the radiator.

Let us know how this test turns out.

[Still Kickin]

This test is for a belt driven clutch fan only.

[Still Kickin]

Oh, and continued operation of your engine beyond normal operating temperature for repeated cycles, WILL cause serious engine damage, including but not limited too, head warpage, head gasket failure etc.

[jbramhall]

Originally Posted by Still Kickin

Here is the procedure to check if your clutch fan is operating at proper efficiency. You will need two persons to do this simple check.

Start the engine and observe the clutch fan operating. (it's spinning)

While you are observing the rotating fan, have the second person shut off the engine.

The clutch fan should spin, no more than one to two and a half complete revolutions, before coming to a complete stop.

If your fan continues to free spin for more revolutions than specified, after shut off, your clutch fan is not operating within design perameters, and needs to be replaced.

The fan needs to pull enough air past the radiator to properly cool the coolant when it circulates through the radiator.



Let us know how this test turns out.

My fan is concealed behind the radiator; so, I'll try this in the AM when I can crawl under the engine and observe the fan directly. Unless you think I can judge by sound or the breeze coming out the back.

[Still Kickin]

Unfortunately not. You need to observe the rotations. At least you will know if that is the problem, and can then deal from a position of authority, with your repair shop.

[jbramhall]

Originally Posted by Still Kickin

Oh, and continued operation of your engine beyond normal operating temperature for repeated cycles, WILL cause serious engine damage, including but not limited too, head warpage, head gasket failure etc.

My mechanic said stop before 230F. What do you think?

[VinceU]

Originally Posted by jbramhall

My mechanic said stop before 230F. What do you think?

I suspect that high temp indication is just that, false indication. As you describe the engine cools quickly without the water pump running! Impossible if truly overheated. Do you carry a IR thermometer? Chose a spot and record the temp on the block. If over heated it will show an increase at that spot.

[Still Kickin]

Unless your moving it to get it to a safe spot to park it, You shouldn't drive it. Mechanics who say its ok to use the graduated dash gauge, I assume thats on the dash for temperature, that is telling you 230 degrees, is not in your best interest. Can't remember what coolants' boiling point is under pressure, but I do know water boils at 212 degrees, at STP ( stand temperature pressure) Not good.

[jbramhall]

Originally Posted by VinceU

I suspect that high temp indication is just that, false indication. As you describe the engine cools quickly without the water pump running! Impossible if truly overheated. Do you carry a IR thermometer? Chose a spot and record the temp on the block. If over heated it will show an increase at that spot.

Sorry if I was unclear, but I do not suspect that the water pump is not running. I think the fan might not come on when it should.

[VinceU]

Originally Posted by jbramhall

Sorry if I was unclear, but I do not suspect that the water pump is not running. I think the fan might not come on when it should.

I understand the water pump is operable, but you indicated you come off the highway and shut it down, no pump. I agree with your first post, the electronics of the fan are goofy, but that's another reason to believe the temp is off. BTW I don't have steam tables with me. The table will indicate if you contain water in a pressure cooker or boiler, the temp needed to boil rises with pressure. IE a 15 psi radiator cap will raise the temp of water boiling from 212 at atmospheric pressure to approx. 250F when contained to 15 psi containment, radiator. Also agree you need to get it repaired soonest, you really don't know where it is.

[jbramhall]

Originally Posted by Still Kickin

Unless your moving it to get it to a safe spot to park it, You shouldn't drive it. Mechanics who say its ok to use the graduated dash gauge, I assume thats on the dash for temperature, that is telling you 230 degrees, is not in your best interest. Can't remember what coolants' boiling point is under pressure, but I do know water boils at 212 degrees, at STP ( stand temperature pressure) Not good.

Well, the boiling point is a function of the pressure...more pressure, higher boiling point. The cooling system is definitely under pressure. I've not let the coolant boil, if that's the concern, but the temp has reached the high 220s. To me, it seems like the logic for the fan likes to come on at initial start, then, if the engine is already hot, the logic tells the fan to continue to run. It just won't start if the trigger temperature is arrived at from the cool side, but it does have a better chance of doing the right thing if the engine is started with an elevated temp already. Then the fan just keeps running (most of the time).

My question is, what temp would be problematic to reach, say, 4-6 times in the next 3 weeks? If 228F is ok, I'll make sure I stop by then. That temp usually triggers the fan to run upon restart.

The "gauge" I'm using is the engine diagnostic readout on the LCD on the dash. Probably not perfect, but better than a dash needle.

[VinceU]

Originally Posted by jbramhall

Well, the boiling point is a function of the pressure...more pressure, higher boiling point. The cooling system is definitely under pressure. I've not let the coolant boil, if that's the concern, but the temp has reached the high 220s. To me, it seems like the logic for the fan likes to come on at initial start, then, if the engine is already hot, the logic tells the fan to continue to run. It just won't start if the trigger temperature is arrived at from the cool side, but it does have a better chance of doing the right thing if the engine is started with an elevated temp already. Then the fan just keeps running (most of the time).

My question is, what temp would be problematic to reach, say, 4-6 times in the next 3 weeks? If 228F is ok, I'll make sure I stop by then. That temp usually triggers the fan to run upon restart.

The "gauge" I'm using is the engine diagnostic readout on the LCD on the dash. Probably not perfect, but better than a dash needle.

That's what I said, the cap is probably rated to 15 psi which is 249.7, I guessed 250F. That's where the mechanics of the system says enough! Around 250 degrees and will open the relief valve and steam out. 230 is about 10% below this rating and is safe, don't push it however. I'm thinkin the clutch is there to cut out the fan when you have enough road speed for draft cooling. Not a diesel engine designer though. Check the cap rating and you are good to go.

[jbramhall]

Originally Posted by VinceU

I understand the water pump is operable, but you indicated you come off the highway and shut it down, no pump. I agree with your first post, the electronics of the fan are goofy, but that's another reason to believe the temp is off. BTW I don't have steam tables with me. The table will indicate if you contain water in a pressure cooker or boiler, the temp needed to boil rises with pressure. IE a 15 psi radiator cap will raise the temp of water boiling from 212 at atmospheric pressure to approx. 250F when contained to 15 psi containment, radiator. Also agree you need to get it repaired soonest, you really don't know where it is.

Here's a table I found...you're right about 15 psi and 250F

http://www.heat-transfer-fluid.com/p...ling-point.pdf

I'd be crazy to go that high, but I wouldn't boil over with a 15 pound cap if I did. I just want to ensure that the engine can take 228F when I try to trigger the fan, even if the coolant is still liquid. The mechanic seems to think so, but it's my rig.

And you're also correct, I need to get this fixed.