BJ42 3B running HOT (1 Viewer)

[joeuen]

Hi guys,


I have a cooling issue with my 3B in my BJ42.


The issue occurs be the ambient temperature 70F or 95F.


Upon first start, the engine will happily idle at ~185F. However, as soon as I hit the highway doing 60mph, it’ll sit at 230F.


Things I’ve noticed:

40mph => 200F

50mph => 210F

60mph => 230F


The engine has always run relatively hot, usually 215F at 60mph, but has now increased which is causing me concern.


Things I have tried/replace:
-Water pump replaced -> 2,000 miles old

-Tried two different types (green & red) of coolant, flushing the system both times.

-Replaced the fixed fan & fan belt

-Replaced the radiator -> 2,000 miles old

-Replaced all hoses -> 2,000 miles old

-Bypassed the factory heater hoses

-Replaced thermostat trying both 180F & 192F types


There is the factory shroud in place, I don’t seem to be losing water at all, and the system never seems to be boiling over to my knowledge.


Any other things I could try? Unless these operating temperatures seem fine

 

[IanB]

Do you have an EGT gauge to see what's going on there? If the engine is running hotter for some reason, it will put additional strain on the cooling system obviously. On a diesel, more fuel, or less air = hotter. Have you recently changed your air filter?

 

[GTSSportCoupe]

What coolant temp gauge/sender are you using and where is it installed? Maybe it is reading high for some reason. At 230F you are close to boiling over, so you'd think you'd be seeing some other signs of problems besides the high temperature on your temp gauge.

 

[joeuen]

Yes, I do have an EGT gauge, at 60mph it reads around 750F.
I still have both the original sender gauge and also an aftermarket Procomp one.
Both of these senders are in the lower thermostat housing.

Haven't recently changed the air filter, it does get cleaned regularly.

Should I perhaps add more fuel using the screw?

 

[gerg]

Feel your radiator for cool spots to see if it's blocked. A thermo temp gun is easiest.

 

[roscoFJ73]

What's the compression like? You said it got worse, was that instantly or over a period of time? I would leave the fuel pump alone for the time being. Its unlikely to change drastically in a short time.

 

[joeuen]

Will check compression this week.

Over time it gradually got worse, not instantly.

 

[roscoFJ73]

When pistons and rings get worn they often flap around in the cyl increasing heat. You would see some smoke and oil usage with it(usually).

 

[joeuen]

Can't really any significant smoke, uses a bit of oil but nothing drastic.

 

[ozcrusier]

I'm guessing your radiator outlets are on the same side like the 2H/12HT ?.

 

[colby1979]

Is this a turbo 3b? What elevation are you at? Do you pull a lot of hills or drive into strong headwinds? What size tire ar you running?

 

[joeuen]

Is this a turbo 3b? What elevation are you at? Do you pull a lot of hills or drive into strong headwinds? What size tire ar you running?

No turbo on this one, pretty much sea level most of the time, barely any hills but have to take the hill at about 45mph otherwise the temperature would rise fairly quickly. Running 33"

I'm guessing your radiator outlets are on the same side like the 2H/12HT ?.

No, they're different

 

[Wes]

Did you burp it when you changed coolant?

 

[joeuen]

Did you burp it when you changed coolant?

Sure did

 

[DEADSALT]

run a stock paper air filter.

a "clean" K&N or the like will be a bit lean,
or turn your fuel up to accommodate for more air and ensuing particulate

 

[colby1979]

I do know that running larger tires works the engine a little harder as they have a limited power band.
If I was in your shoes I would fix the fan in a non permanent fashion and see if it brings your temps down, this worked for me on a turbo motor that tended to run hot. If that works there are numerous ways to eliminate/disable the clutch permanently.
Another thing to look into is a custom rad with larger capacity and higher fin count.

 

[joeuen]

run a stock paper air filter.

a "clean" K&N or the like will be a bit lean,
or turn your fuel up to accommodate for more air and ensuing particulate

It is running a stock filter, but out of curiosity, a friend of mine is running a K&N filter in his stock 3B and is running fine. Would a lean mixture rise coolant temperatures this significantly? Based on my current EGTs I don't think I could raise the fuel that much would it?

I do know that running larger tires works the engine a little harder as they have a limited power band.
If I was in your shoes I would fix the fan in a non permanent fashion and see if it brings your temps down, this worked for me on a turbo motor that tended to run hot. If that works there are numerous ways to eliminate/disable the clutch permanently.
Another thing to look into is a custom rad with larger capacity and higher fin count.

I can't run a clutch on my motor, I am in AU and our 3B motors came with a fixed fan. No suppliers in AU stock the suitable waterpump which accommodates the viscous and appropiate fan.

 

[IanB]

Lean = cool on a diesel, I don't think that's your issue. If anything, your symptoms would better match a clogged air filter restricting air intake leading to a rich condition.

 

[joeuen]

Lean = cool on a diesel, I don't think that's your issue. If anything, your symptoms would better match a clogged air filter restricting air intake leading to a rich condition.

Wouldn't that lead to much higher EGT?

 

[IanB]

Wouldn't that lead to much higher EGT?

If you're air filter was restricting flow, then yes that could contribute to higher EGT's as it causes the engine to run more rich than if it was getting more air.

It's important to remember, diesel tuning principles are backwards from gas engines.