Headgasket leak?

[FJBen]

So always good news right…

I’ve had a leak start within the last few weeks. Never been overheated, runs amazing.

Starting seeing a little coolant loss, not much but found it around the bell housing. Put dye in and black lighted.

Cleaned it all off.

Test drive

No coolant in oil or vice versa. Seems minor and completely external.

So talked to my machine shop and he said you could retorque it but it Probabaly won’t fix it. So sounds like about the only thing to do is pull the head and put a new gasket on it.

Any other advice or thoughts?

 

[FJBen]

I rebuilt this engine in 2019. Zero issues, runs amazing. New head bolts, mls gasket, block set with correct counterbore and head redone.


Now I did test a center head bolt at 10ft lbs less than spec and was able to move it a little bit before it clicked. Now I’ve been running fine leak free (well headgasket leak free) since 2019 and just over 40,000 miles. Not sure why now…

 

[Eurasiaoverland]

Any fluid running down the head can be entrained onto the lower edge of the head and will tend to run along the gasket area, so it could be a core plug in the head. I've also heard about suspected lift of the head on engines with the boost turned up, but not sure if that has been proven.

I would monitor it for now.

 

[FJBen]

Any fluid running down the head can be entrained onto the lower edge of the head and will tend to run along the gasket area, so it could be a core plug in the head. I've also heard about suspected lift of the head on engines with the boost turned up, but not sure if that has been proven.

I would monitor it for now.

Yeah I’ve looked all over. I don’t see any leaks from plugs. This looks to be 100% from the gasket

I’m going to check that plug, but there doesn’t seem to be any dye trace on it.

 

[FJBen]

Seems like it’s for sure the gasket.

 

[Eurasiaoverland]

Damn, that's bad news.

Was ait a genuine Toyota MLS? Was the head and/or block decked? I know the original 13B bitumen type head gaskets are prone to leaking, but not MLS gaskets. Was it run for long with a leaking head gasket prior to rebuilding?

Hope it's an easy fix.

 

[FJBen]

Damn, that's bad news.

Was ait a genuine Toyota MLS? Was the head and/or block decked? I know the original 13B bitumen type head gaskets are prone to leaking, but not MLS gaskets. Was it run for long with a leaking head gasket prior to rebuilding?

Hope it's an easy fix.

Genuine Toyota MLS. Full rebuild 5 years ago.
Block decked 2thousandths to set counterbore
Head rebuilt and resurfaced
Everything squared up and runs amazing. Literally just an external leak.

I do have aftermarket turbo that’s been on for 1.5 years, max boost was like 18-19 and that was only a few times testing. Most of the time it was rarely over 14-15psi.


Do you know if the MLS gasket has a different torque spec than the 87ft lbs that the manual states?

 

[Eurasiaoverland]

The later B engines (3Bii, 14B, 15B) that I am familiar with came with MLS gaskets from factory and have torque specs of I think 49 Nm, then +90º, then +90º again. Which would end up a lot more than the 118 Nm which my local museum tells me is 87 ft lbs . 118 Nm is barely above wheel nut torque - the head bolts onone of these engines need the engine stand propped against a wall and a cheater bar on my breaker bar.

I thought this was down to the switch to torque-to-yield bolts, but it would also tie in with the switch to a MLS head gasket.

Good thought though - I had not considered that. I would get a set of 3Bii bolts (18 x 90910-02084) and run with those if you are taking the head off.

Sounds like you did everything perfectly, so unless (and I really hope it's not the case) the block or head has somehow cracked, clamping pressure is the only thing I can think of having failed.

 

[FJBen]

The later B engines (3Bii, 14B, 15B) that I am familiar with came with MLS gaskets from factory and have torque specs of I think 49 Nm, then +90º, then +90º again. Which would end up a lot more than the 118 Nm which my local museum tells me is 87 ft lbs . 118 Nm is barely above wheel nut torque - the head bolts onone of these engines need the engine stand propped against a wall and a cheater bar on my breaker bar.

I thought this was down to the switch to torque-to-yield bolts, but it would also tie in with the switch to a MLS head gasket.

Good thought though - I had not considered that. I would get a set of 3Bii bolts (18 x 90910-02084) and run with those if you are taking the head off.

Sounds like you did everything perfectly, so unless (and I really hope it's not the case) the block or head has somehow cracked, clamping pressure is the only thing I can think of having failed.

Interesting….

I opened up and checked the head bolts. The ones on the exhaust side were all a little loose to torque spec. I retorqued but it’s still leaking.

Do you have a manual or specs for the 3Bii or 14bt/15bt? I

 

[Eurasiaoverland]

15B-F FSM manual availability

Before I get started on this journey with a 15B-F, just wondering if anyone knows of a manual available to download or purchase? I note that a few people are chasing one to be scanned in via the Online Manuals sticky thread, and have found a few images of a manual the internets but its in...

forum.ih8mud.com

I got mine from this thread. This is the 3B, 14B, 15B-F, 15B-FT engine manual. Toyota do not differentiate between various 3Bs, but this is the August 1988 3B which has the same block as the 14B.

 

[FJBen]

15B-F FSM manual availability

Before I get started on this journey with a 15B-F, just wondering if anyone knows of a manual available to download or purchase? I note that a few people are chasing one to be scanned in via the Online Manuals sticky thread, and have found a few images of a manual the internets but its in...

forum.ih8mud.com

I got mine from this thread. This is the 3B, 14B, 15B-F, 15B-FT engine manual. Toyota do not differentiate between various 3Bs, but this is the August 1988 3B which has the same block as the 14B.

I guess the big question: are the TTY bolts the same size and thread as the 13bt block?

I think there is only 1 size headgasket available for the 13bt as well

 

[Eurasiaoverland]

The bolts are M12x1.25 on the 3Bii etc. Length I don't know off the top of my head but I can measure one later if it helps.

Yes, only one size of head gasket (-58110 IIRC) for the old 3B and 13Bs, so one less thing to check.

 

[FJBen]

That would be great if you could measure length. I may have a spare head bolt still, I will have to look.

Plus they have liners and I know piston protrusion was right so that headgasket should Be right.

 

[FJBen]

 

[roma042987]

I had a 3b headgasket leak in that same spot before but only under heavy loads and boost. I ran it that way for many years and miles. Are your head bolts 6 or 12 point? I believe that is the designation between TTY and the earlier design.