Chasing a Slow Coolant Leak – 1996 80 Series, 190K, HG Done

[LimitingFactor]

Finally got around to blowing apart the cooling system. None of the gaskets appear be failed Pressure tested the cooler and it checked out fine. There was one suspicious hairline crack on the oil pressure relief galley of the aluminum housing so I am debating leaving it, jb welding it, or get a new housing?

 

[Marvelicious]

If it were me, I'd do a dye penetrant test on that to see if it's anything, because it kinda looks like it could be just a surface flaw and might even be from the mold, not actually a flaw in the part. You might watch a few youtube videos to explain the process, but it's not super complicated. I'd go for "water washable" dye, and wash it thouroughly. If it's really cracked, it'll be pretty obvious. If you wind up in doubt, post the pics. A few bucks in chemicals from the local welding shop will tell you whether you have something to fix, or not.

Alternatively, someone who knows what they're doing with a TIG torch could just grind a little groove there and fill it with fresh metal. Still, better to only fix it if it's actually a problem, which brings me back to my first idea.

 

[Kernal]

Can you circle the area you think has a crack?

Did you find any coolant residue on the outside of the cooler cover?? The interior appears to have zero corrosion which seems
to be where some leaks start.

 

[LimitingFactor]

Good point about a dye pen test, I don't have a kit and they only cost a little less than what a new OEM housing runs..
The area in question is circled:

 

[Marvelicious]

Good point about a dye pen test, I don't have a kit and they only cost a little less than what a new OEM housing runs..
The area in question is circled:
View attachment 4178953

To me, it's just something worth keeping on the shelf, but if you're only likely to use it once, and the OEM housing is that cheap, I'd just replace it, but I really don't think that's anything. Still, I'd want the peace of mind.

Another idea: Get a couple of rubber plugs to fit the holes, drill one to fit an air nozzle, and pressure test it with soapy water...

 

[LimitingFactor]

I decided to move forward with reassembly. I made a few block off plugs to pressure check the oil cooler and just re used them for the housing. I dunked the housing in water while pressurized and didn't see bubbles so I'm confident now it wasn't a crack.
Still doesn't confirm where the original leak is though? I'm also doing a rear heater delete, water pump and PHH while the system is drained and apart.
I'm going to drive it for a while and see if this fixed the issue.

 

[Marvelicious]

Glad to see the 'ol calibrated eyeball is still calibrated. Still, it sucks that you're still hunting for the problem.

 

[Kernal]

Nice custom made pressure testing tool

 

[ADP91]

Hi LimitingFactor,

I had this exact issue - ironically on a similar timeline (last fall till now). I was losing a steady but small amount of coolant with no external leaks. Did a Blackstone analysis and confirmed coolant contamination and did the combustion gas coolant test (radiator neck) and it came back negative.

My compression/leak down test results were pretty bad so I decided to take it in to a local shop for HG replacement and inspection. What they found was a crack in the cylinder head. So we ordered a new OEM head from Toyota ($3500 CAD plus shipping). The engine is back together and it appears the issue is resolved.

Probably not the news you want to hear by just wanted to share my similar experience.

Let me know if you have any questions.

 

[MissahPapaJ]

Really cool idea making those block off test ports!

 

[MissahPapaJ]

Hi LimitingFactor,

I had this exact issue - ironically on a similar timeline (last fall till now). I was losing a steady but small amount of coolant with no external leaks. Did a Blackstone analysis and confirmed coolant contamination and did the combustion gas coolant test (radiator neck) and it came back negative.

My compression/leak down test results were pretty bad so I decided to take it in to a local shop for HG replacement and inspection. What they found was a crack in the cylinder head. So we ordered a new OEM head from Toyota ($3500 CAD plus shipping). The engine is back together and it appears the issue is resolved.

Probably not the news you want to hear by just wanted to share my similar experience.

Let me know if you have any questions.

View attachment 4180017

Was that the install price? 3500$ or just the head? When you did the head did you do new cams and everything or did you swap things over?

 

[ADP91]

Was that the install price? 3500$ or just the head? When you did the head did you do new cams and everything or did you swap things over?

$3500 was just the head I believe. Machine shop had to replace the cam with a used one as it had a small crack in the end. Was already planning new valves, seats, springs, etc. so that went into the new head. So essentially everything new except a used but good cam.