Turbo 3B Overheating (1 Viewer)

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I guess I’ll just remove the turbo and go back to naturally aspirated. I’m not sure I can afford an engine swap, and I definitely don’t have the experience for that either.

Don't give up yet. Even if you do that you still have to fix this problem regardless. May as well fix the problem and keep enjoying the turbo.

Just run a lean tune, and make sure the cooling system is tip top as is maintenance of the engine and you should be ok. For all regular driving it should be fine. If you are in super hot weather going up big highway hills at speed and it gets hot, just slow down and take it easy. It's not like the 40 series are big heavy trucks. Moving one should be well within the capability of a well tuned 3B turbo.

I run Evans Coolant in mine to help protect the head. It transfers heat a little bit worse, but also doesn't boil until 380F. So works well to keep the head at an even temperature to reduce stresses that can cause cracking around the pre-cups. I get my POS little 2LTE damn hot towing a camper every year, and have had no head problems with the Evans.

IDI turbo can be fine if you just live within the limits. It's sort of like comparing the old Chev 6.5 turbo to the Duramax 6.6. The former was IDI turbo, the later DI turbo. The 6.5 can be ok if it's well maintained with a good cooling system and driving within it's limits. Another comparison is the old Ford IDI 7.3 turbo vs the newer power stroke 7.3. Same deal.

If you were to upgrade, a direct injection B motor would make the most sense to me. Direct injection fixes the heat problems as the combustion chamber is in the piston instead of cylinder head. Think: 13BT,14BT,15BFT or 14B,15BF. They're pretty much a bolt in replacement for a 3B. Apparently the 15BF even normally aspirated makes great power.
 
650/700 F is nothing, even if it's Post turbo. I can't imagine the EGTs run that low, even factory doesn't run that cool so I'm definitely questioning that reading.

I'm guessing something might be blocked in the head or cracked or something. There is no way there should be coolant spitting out at 70kmh. That would lead me to believe that coolant isn't flowing right and getting cooled at all.

Can you go back to the original fan/clutch setup with shroud?
I would replace that waterpump. You said you checked it, how did you do that? You can fix everything else but if that water isn't circulating from the pump, it's going to overheat quickly.
I just made sure that the heater was working, in order to check the water pump. It’s really hot after a few minutes. I can go back to the fan clutch and shroud. I saved all the original parts just in case.
 
a turbo’d 3B is a joy to drive,
like GTSS said “don’t give up on the turbo, there’s something else going on.

post some/lots pics of what’s been done under the hood

how convoluted is the intake, are you running stock exhaust, etc...
 
a turbo’d 3B is a joy to drive,
like GTSS said “don’t give up on the turbo, there’s something else going on.

post some/lots pics of what’s been done under the hood

how convoluted is the intake, are you running stock exhaust, etc...

I had to remove the stock air box to run the tubing for the intercooler, hence the cone filter. Exhaust, not sure what what I have even counts as exhaust. It ends about two feet from the exhaust side of the turbo. I have a new water pump in the box but I hesitate to install it bc the heater works great. And from what I understand, if the WP was clogged or not working then the heater would be blowing cold air, and not allow coolant to flow to the radiator. My radiator can cook an egg so I’m guessing it’s getting circulated coolant. Am I wrong about that? There is no oil leaking anywhere on the truck 🤞.

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Looks great! Is that what they call a 3B-II? Has a rotary injection pump which did not come on the Canadian BJ70's of the same year.... Must be a Japan market thing.

I think you've done everything right. Other than if it were me I'd probably go back to a mechanical fan at some point; but I don't think that is your primary problem here.

Your symptoms are classic cracked head or blown head gasket. Coolant gets pressurized with combustion gasses as soon as the engine is under load...and, well...you know the rest of the story. If it were me, I'd order an MLS head gasket (and associated parts; head bolts etc.), pull the head, and see what's going on.

It's not that tough of a job. Just follow the FSM carefully and you can't go wrong.
 
if what I think is the intercooler, then that's not much of one, and definitely not in a good location. Also, I would install a aftermarket water temp gauge to verify your temps. my factory gauge reading half was showing about 245F on the aux gauge. But yeah, it shouldn't overheat at 70km.
 
Looks great! Is that what they call a 3B-II? Has a rotary injection pump which did not come on the Canadian BJ70's of the same year.... Must be a Japan market thing.

I think you've done everything right. Other than if it were me I'd probably go back to a mechanical fan at some point; but I don't think that is your primary problem here.

Your symptoms are classic cracked head or blown head gasket. Coolant gets pressurized with combustion gasses as soon as the engine is under load...and, well...you know the rest of the story. If it were me, I'd order an MLS head gasket (and associated parts; head bolts etc.), pull the head, and see what's going on.

It's not that tough of a job. Just follow the FSM carefully and you can't go wrong.
Thanks a lot. I guess it can’t hurt, except the wallet, to change the head gasket…
 
if what I think is the intercooler, then that's not much of one, and definitely not in a good location. Also, I would install a aftermarket water temp gauge to verify your temps. my factory gauge reading half was showing about 245F on the aux gauge. But yeah, it shouldn't overheat at 70km.
Yeah you’re right about the intercooler. It’s a SMIC from a 2000’s VW. I don’t really have anywhere else to put it. There isn’t much room in front of the radiator, so there it went. It actually does a pretty alright job where it is. Even with the engine overheating the intake tube is barely warm.
 
If you don’t have a/c then you can get a generic 2.5” thick intercooler mounted in front of the radiator and still keep the grill. Depending on how tall a intercooler you get you may need to modify the latch. I did this on the 86 BJ70 I used to have
I don’t have a/c. I’ll look into that after the head gasket. Thanks a lot.
 
Thanks a lot. I guess it can’t hurt, except the wallet, to change the head gasket…

That's the way I'd look at it. Even if for some bizarre reason it's not the core problem, at least you won't have to fear blowing your head gasket in future after you've installed the MLS one.

Before yanking the head, you could use a thermal imaging camera, or maybe a couple temp probes (measure coolant temps in and out of rad) to make sure your rad/fan setup is able to dump sufficient heat. I can't see it being that bad, but maybe just completely eliminate it as a possibility first. That, or go back to the mechanical fan and shroud with a OEM new viscous hub.
 
Just thinking of your intercooler now that @coldtaco mentioned it. I missed seeing it when I first looked at your pictures. I can't quite tell, but is it blocking air coming out of your electric fan from the rad? If it's blocking in any way, it could really reduce the air flow substantially.

Also, I think that size intercooler can be fine when using a fairly well sized modern turbo operating within it's efficiency range. A 3b doesn't flow much air due to low rpm operation being a diesel. Main thing tho, is it does need to be in front of the rad, not behind.
 
That's the way I'd look at it. Even if for some bizarre reason it's not the core problem, at least you won't have to fear blowing your head gasket in future after you've installed the MLS one.

Before yanking the head, you could use a thermal imaging camera, or maybe a couple temp probes (measure coolant temps in and out of rad) to make sure your rad/fan setup is able to dump sufficient heat. I can't see it being that bad, but maybe just completely eliminate it as a possibility first. That, or go back to the mechanical fan and shroud with a OEM new viscous hub.
I was thinking about upgrading to a larger clutch fan before I switched to the electric. Maybe I should just do that.
 
Just thinking of your intercooler now that @coldtaco mentioned it. I missed seeing it when I first looked at your pictures. I can't quite tell, but is it blocking air coming out of your electric fan from the rad? If it's blocking in any way, it could really reduce the air flow substantially.

Also, I think that size intercooler can be fine when using a fairly well sized modern turbo operating within it's efficiency range. A 3b doesn't flow much air due to low rpm operation being a diesel. Main thing tho, is it does need to be in front of the rad, not behind.
The intercooler is behind the fan. The fan is attached to the radiator and it’s a puller, so it’s got good airflow.
 
The intercooler is behind the fan. The fan is attached to the radiator and it’s a puller, so it’s got good airflow.
Maybe. Sometimes having blockage on the output of a puller can create a high air pressure area that is detrimental to cfm, as the 'pulled' air has no where to go. Anyhow, hard to tell from this end of the internet from just a picture.
 
Maybe. Sometimes having blockage on the output of a puller can create a high air pressure area that is detrimental to cfm, as the 'pulled' air has no where to go. Anyhow, hard to tell from this end of the internet from just a picture.
I can see that.
 

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