Possible cracked head ?

[crushers]

Make sure that the radiator is FULL and the cap is good, otherwise if the radiator is low or the cap is bad you will get alot of fluxuation of coolant in the overflow. The just because you have fluid in the overflow doesn't mean you have a full cooling system. Make sure it is cool before removing the cap and filling it. Most of the time the #4 combustion chamber cracks first but slightly and all you will see is bubbling, no smoke and I have never seen water in the oil with a 2LT. Sometimes if the crack is minor I have seen them go weeks in between overheating. It will overheat one day and not the next but there usually was a slight bubbling and it progressively gets worse.

Randy, (or is it steve?)
have you installed any pyros to test the EGTs of these engines?
cheers

 

[Greg_B]

i can confirm witnessing 3Bs with cracked heads and no real obvious signs of the cracking till the head was removed.
this account by Greg is completely plausable...
cheers

Oh...this was totally different then the typical cracks that 3B heads seem to get...show no symptoms and don't slow them down.

This was strange, in that there was only one symptom...a bubbling rad. Everything else in the trouble shooting routine was negative. And it was not a 3B, nor any truck/engine that we own.

gb

 

[108Cruz]

And I have seen the situation where there was no white smoke, crystal clear exhaust, no evidence of combustion gases in the coolant with the diesel coolant tester, and no coolant in the oil. The only evidence was a little bubbling in the coolant, and immediate pressurization of the coolant system (within one minute). It was not overheating when driving, and would push the coolant into the overflow. A cracked head was verified when removed.

hth's

gb

Greg, when you say immediate pressurization of the coolant system, do you mean on a cold start up and the upper and lower rad hoses get hard due to pressure ?

Peter

 

[crushers]

Oh...this was totally different then the typical cracks that 3B heads seem to get...show no symptoms and don't slow them down.

This was strange, in that there was only one symptom...a bubbling rad. Everything else in the trouble shooting routine was negative. And it was not a 3B, nor any truck/engine that we own.

gb

i was agreeing that it is possible to show no apparent signs and still have a cracked head.
i have bought many BJs for parts in the past with no "apparent" causes for concern and strip the engines ready for rebuild and found the cracks between the valves.
ooops.
hence the number of blocks i have sitting here machined ready for reassembly but no heads.
cheers

 

[cruiser_guy]

i was agreeing that it is possible to show no apparent signs and still have a cracked head.
i have bought many BJs for parts in the past with no "apparent" causes for concern and strip the engines ready for rebuild and found the cracks between the valves.
ooops.
hence the number of blocks i have sitting here machined ready for reassembly but no heads.
cheers

I'll agree with that! Every 3B I've stripped (4 to date) all had cracked heads. Only one, the '84 was obvious or even showed symptoms.

 

[Greg_B]

Greg, when you say immediate pressurization of the coolant system, do you mean on a cold start up and the upper and lower rad hoses get hard due to pressure ? Peter

Yes. It should build pressure slowing...say over 5-7 minutes as it idles away and warms up. This was within the 1st minute.

hth's

gb

 

[Greg_B]

i was agreeing that it is possible to show no apparent signs and still have a cracked head.cheers

No harm no foul Wayne. Many 3B's have cracks and are still completely serviceable it seems. I was showing that it is possible to have a cracked head that would show one symptom (coolant bubbling) and none of the other obvious symptoms that Charles was saying had to be showing to confirm a cracked head.

Charles, I had a hard time convincing others, especially with no change in color of the liquid for testing coolant system for hydrocarbons, but my gut was saying cracked head...

I was not happy to be right, at all. It was simply more info for the databank.

108Cruz...I hope it is not for your sake too. Keep on troubleshooting and gathering info. If you have to get into it, do a search on this site. Allhead seems to be the s***e for knowledge and product to deal with it...if you have to go there.

hth's

gb

 

[light_duty]

BTW, I'll soon be posting a thread detailing the head replacement on my 2L-TE. I'm just waiting for some pics that my buddy took of the actual head install.

 

[108Cruz]

Update.

I seemed to have solved the problem ( I hope )

Today I looked at the rad cap more closely and the rubber was definately brittle and cracked. Most likely original cap.

I relpaced the cap which I obtained from a nearby Toyota mechanic for $ 12.
Toyota wanted $24.

The truck was started up and I let it idle for 10 mins. Pressure was slow to build up in the hoses .

After I shut the truck off , there was no more gurgling or bubbling noted in the overflow tank.

It seems at this time that it was a bad rad cap.

Thanks to all those who responded

Peter

 

[Jan-78FJ40]

Update.

I seemed to have solved the problem ( I hope )

Today I looked at the rad cap more closely and the rubber was definately brittle and cracked. Most likely original cap.

I relpaced the cap which I obtained from a nearby Toyota mechanic for $ 12.
Toyota wanted $24.

The truck was started up and I let it idle for 10 mins. Pressure was slow to build up in the hoses .

After I shut the truck off , there was no more gurgling or bubbling noted in the overflow tank.

It seems at this time that it was a bad rad cap.

Thanks to all those who responded

Peter

excellent fix-$12 for a rad cap vs $1000 for a head

 

[light_duty]

Whew!

Good on ya.