3B Overheating - help needed! (1 Viewer)

[Diesel Wannabe]

So, I’ve been working on my BJ40 (42) project for two years now and it’s looking great, it’s just overheating. Here’s some background:

• Engine/tranny – 3B/H55 from a 1985 Canadian BJ70 (12 volt). It did sit in a barn for 20 years, but I got it running and am getting 420psi compression across all four cylinders so I didn't do much to the engine
• Frame/running gear – 1979 BJ40 (that’s how it’s titled so I call it a 40/42 since it has the H55)
• Turbo – Keith42’s kit
• Radiator – aluminum 4 row, electric fan
• I live in California and have been building this in Indiana at my uncle’s garage, with a lot of his help, and with lots of trips from California
• I planned to take it to California, so I didn't plump in a heater core or heater hoses
• Water pump and thermostat are new, so are all hoses...

Now for the symptoms. Basically, the system boils and spews coolant out of the overflow bottle, quite a bit of it actually. I’ve tried quite a few fixes and have run all of the tests that I can think of. I don’t fully understand the coolant flow pattern through the head/block… I appreciate any help/advice/knowledge you can share.

• I confirmed flow through the radiator
• I confirmed the thermostat is opening (it’s been a while, but I think it was 180 or 185 F)
• I also ran it without a thermostat
• I confirmed that the water pump is pumping (took the top hose off the radiator and ran it to an empty coolant jug with the thermostat out
• I’ve gone to great lengths to “burp” the system to get all of the air out – including loosening a sensor below the thermostat to let out the air under the thermostat
• Since the 3B sat for so long, I flushed it with water for 20 minutes, backflushed it from the rear driver’s side port in the head, ran radiator flush for 20 minutes, flushed it again, ran it for 20 minutes with water, drained and refilled it.
• After all of that, still running hot. Then I realized that I didn’t provide a path for the water to get from the rear of the engine back to the water pump – DUMB! So, I installed nipples on the rear driver’s side port in the head and the input port on the water pump. I was kicking myself and we really thought that would solve the issue. No luck, same overheating/boiling over.
• There are still ports that I have plugged off since I don’t have an oil cooler and no heater. Anyone know if I need to open any of these and route them somewhere to get proper coolant flow? I’m guessing that coolant is just sitting in the head/block until it gets too hot and boils.

Thoughts?

Pictures below.

 

[duncanrm]

Does it spew out coolant soon after starting or only after (for example) a hill climb or extended period of idling?

Have you run the engine with the radiator cap off and the radiator full to see if there's any bubbles/smoke coming out?

 

[sodafeld1]

you can also get the dye test which tests if there is exhaust entering the coolant, the ebay one works ok, bubbles whilst running is a more direct sign. There are also cheap radiator pressure testers to see if your radiator holds pressure, which is what a rad shop does first off the cuff. And maybe even your radiator cap which is a cheap replacement.

Did gunk come out when you flushed? If so, there maybe more, citric flush can help. The capillaries in rads are quite fine.

Am I comprehending with what you are writing that you don't have an oil cooler?!

 

[AussieHJCruza]

Check the cylinder head and head gasket to start with.

Also, get rid of the electric fan and put a proper OEM clutch fan on.

 

[Diesel Wannabe]

Does it spew out coolant soon after starting or only after (for example) a hill climb or extended period of idling?

Have you run the engine with the radiator cap off and the radiator full to see if there's any bubbles/smoke coming out?

It boils over after a cold start, about 3-4 minutes of idle warmup, and then about 4-5 minutes of driving in the neighborhood with some stop signs and 30 mph max.

I have not run it without the radiator cap. I'll try that today. Thanks.

 

[Diesel Wannabe]

you can also get the dye test which tests if there is exhaust entering the coolant, the ebay one works ok, bubbles whilst running is a more direct sign. There are also cheap radiator pressure testers to see if your radiator holds pressure, which is what a rad shop does first off the cuff. And maybe even your radiator cap which is a cheap replacement.

Did gunk come out when you flushed? If so, there maybe more, citric flush can help. The capillaries in rads are quite fine.

Am I comprehending with what you are writing that you don't have an oil cooler?!

I'll try the rad cap off, I didn't mention that I did try a new cap with 18psi.

Some small black specks always seem to come up to the rad filler neck no matter how much I flushed it.

Correct on the oil cooler. I don't think these Canadian 3Bs used them.

Thanks

 

[sodafeld1]

small black specks could be carbon from exhaust entering your coolant, that doesn't sound good.

 

[Diesel Wannabe]

small black specks could be carbon from exhaust entering your coolant, that doesn't sound good.

Agree. I'll test it later today. Honestly, I'm no that sad about it, I'll feel better having the head machined, valves...

Recommendations on a source for an OEM head gasket set + head bolts?

 

[bj70bc]

There is an integral oil cooler on the passenger side of the engine underneath a cover on the side of the block the oil goes through it as part of the natural flow pattern.
Get rid of the electric fan and get an original one that has a working fluid clutch in it
Both of the nipples out of the head are for the heater cores (in dash and backseat, so they dont need to be hooked up)
You could have a bad headgasket..... this is my guess
You should get an actual toyota headgasket (3b, 13bt).... no aftermarket crap, mls toyota headgasket (available anywhere), and reuse the bolts, they are not torque to yeild, so reuseable

 

[OGBeno]

Agree. I'll test it later today. Honestly, I'm no that sad about it, I'll feel better having the head machined, valves...

Recommendations on a source for an OEM head gasket set + head bolts?

Available from any Toyota dealer.

 

[Diesel Wannabe]

I ran it with the radiator cap off and got plenty of air bubbles, they didn't stop coming after several minutes of idling. Had to be a couple of gallons of bubbles in total. Faster when I increased the RPMs, but that could have been cavitation from the pump.

Also, we examined the black flecks up close and all agree that they look like small insect bodies, like tiny beetles. Not sure where they are coming from since it's been flushed so much.

There is an obvious crack in the head gasket towards the front from cylinder 1. That doesn't explain the leak to water. Also, bolt #7/18 was tight all of the way out and had some corrosion down in the threads.

Head is removed and ready for the machine shop.

Pictures below.

 

[bj70bc]

that was fast
there are 2 coolant holes at the back and along the passenger side of the block, combustion gasses like to enter there, mine went on cyl 2+3 passenger side and the back

let see the underside of the head......between the valves (look very closely)

 

[duncanrm]

let see the underside of the head......between the valves (look very closely)

Yep, this is the money shot.

 

[Diesel Wannabe]

that was fast
there are 2 coolant holes at the back and along the passenger side of the block, combustion gasses like to enter there, mine went on cyl 2+3 passenger side and the back

let see the underside of the head......between the valves (look very closely)

It took about 2 hours to pull the head after letting the engine cool down after the bubble test. It was probably fast and easy since we'd already dealt with the old bolts/nuts on the exhaust when we installed the turbo kit.

We'll inspect the underside of the head and get a picture if I can.

 

[-MaTTi-]

Remember to use OEM head gasket (MLS) instead of that carbon one.

 

[Diesel Wannabe]

Remember to use OEM head gasket (MLS) instead of that carbon one.

I am planning to use OEM. I tried to order it from my local Toyota dealer but they couldn't get it. I am looking for a source in Canada.

What does MLS mean?

 

[Diesel Wannabe]

So the machine shop says that the head is in great shape, pressure tested and true/flat.

We looked hard but didn't find evidence of the head gasket failure despite looking where we were pointed to. I was told that these metal (copper or brass?) rings built into the HG were designed to fail, kind of like a fuseable link. See the picture below, is that a HG failure point?

 

[-MaTTi-]

I am planning to use OEM. I tried to order it from my local Toyota dealer but they couldn't get it. I am looking for a source in Canada.

What does MLS mean?

Multi Layer Steel. Part number 11115-58110