BJ-71 / 13BT overheating issue - Any tips? (1 Viewer)

[TOPacifica]

Hey all - hoping someone can steer me in the right direction. My JDM 1987 BJ-71 with the 13BT engine suddenly starting overheating. Coolant was a bit low, but it started overheated again. I had white smoke from tailpipe that seemed like steam only.

First thing I did was change cap for genuine Toyota. Seeing some corrosion in housing, also changed the thermostat (90916-03080) and thermostat gasket. I did a full system flush, running some cleaner through, and refilled fresh. I thought that must be it because thermostat was a little crudded up.

But after this, still had white smoke, and in fact it seemed more oily now. Crap - head gasket?

I ordered a test kit as well as an alternate diesel test fluid. BUT I can't get either forumlas to turn color indicating a head gasket issue. Also, when I warm up to the level in picture, 10-15 minutes, thermostat open I assume, then drain some coolant from radiator bottom drain its cold. Is that normal? What should I be looking at next?

Leak test: can't get it to show any sign of exhaust in cooling system:

Coolant drained from bottom of radiator is cold, when showing this level on dash:

 

[Clutchee]

Do you have access to temp/ IR gun?
If so, shoot top radiator hose, and bottom.

Then look at radiator. Same top vs bottom temp.

Is you fan clutch working, is it locking up.

 

[AirheadNut]

Coolant in the bottom hose should be cool/tepid even with the engine at operating temperature. Last week I got home from a highway run in 95°F ambient temperatures, coolant temp exiting the engine was around 200°F and the lower rad hose was cool enough to hold on to comfortably.

 

[Behemoth60]

Almost certainly a head gasket.
I've had several 13BT head gaskets go.... they were all factory originals, and after installing the MLS head gaskets available now from Toyota, they are good forever.
The nasty thing about the 13BT head gasket failures is that they are not like a typical gasser failure... you cannot test them at idle in a garage... they only really leak when under max load, something you cannot easily replicate in a garage without a chassis dyno. And mechanics that are familiar with old Chev/Ford head gasket leaks will be confused by this.
Good news is that the replacement gaskets are excellent, available, and inexpensive. And it is an easy saturday job to replace the head gasket with normal hand tools and a torque wrench. It really is not that complicated. Don't even take the intake/exhaust manifolds off. Get a friend and lift who whole thing out.

 

[FJBen]

Cant add much more to what @Behemoth60 said.

I will add, if you do the headgasket, might as well pull the radiator to get it tested and looked at, leaks can be hidden behind shroud. get a new water pump, get a new fan clutch and replace all heater hoses.

Then at least you know the cooling is up to spec.
Lastly add a water gauge, digital or whatever that monitors coolant temp so you have an actual idea, not just the vague Toyota gauge that will read normal even without coolant.

 

[TOPacifica]

Thanks!! Lots of great info here. I didn’t realize temp would run that cool at radiator bottom. I do have the IR non contact thermometer so that’s easy to check. And thanks @Behemoth60 for the info on testing with the kits. I had a feeling this was not going to reveal head gasket issue but had to give it a try. Thanks @FJBen for advice on what else I should be doing at the same time. I’ll get my shopping list going on this

 

[bj70bc]

bubbles in the overflow tank is an indicator too if the HG is bad

 

[TOPacifica]

bubbles in the overflow tank is an indicator too if the HG is bad

Thanks @bj70bc. I have one of those funnel setups for filling / purging air. In other engines they work ok for indicating head gasket issue when you see exhaust bubbles. Are those effective on 13BT?

Like this:

https://www.harborfreight.com/no-spill-radiator-funnel-kit-58423.html?utm_source=google&utm_medium=cpc&utm_campaign=12144811130&campaignid=12144811130&utm_content=132904850139&adsetid=132904850139&product=58423&store=494&gad_source=1&gbraid=0AAAAADAHb4dvqEWv5TQLGIF4t9WfXmFsZ

 

[bj70bc]

never tried one of them...