Coolant In Bore 1HZ

[Crackity]

Hey all, have a technical question someone may have had experience with.

Just did the Big End Bearings in my 93 Cruiser, 1HZ with aftermarket turbo. No probs there, all was in great condition, new bearings in fine.

HOWEVER. After the car sat for two days with the sump and old bearings removed while the new bearings were being shipped, a tiny bit of coolant started weeping down into the bore of number three cylinder. The leak was not present when I first pulled the sump off or the two days after I pulled the sump off. Only appeared on the third day of sitting. The car has never run hot and doesn't use any coolant. The oil is clean. My mechanic seems at a bit of a loss to explain it.

I've since put the car back together with the new bearings and started and run it and it's running fine, no overheating.

Anyone have any ideas? I'd rather head the problem off at the pass before it causes damage...

Muchas Gracias

 

[Beno]

Unfortunately you will have to take the head of but check around the precombustion chambers for all cylinders as it is not uncommon for there to be cracks between the pre and main combustion chambers and when fitted with after market turbo it only makes the conditions worse for the head.
Or a weeping head gasket.

Do you have a EGT gauge fitted. The factory temp gauge is known to be lazy and your engine can be running considerably hotter than you think.

Also the pistons have been known to crack but this is more related to the later 1hz motors in the HZJ 105 Cruisers with the lighter piston crowns. How long since the injectors and pump were overhauled.

 

[StarCruiser]

Excuse my ignorance here but are the 1hz engines indirect injection (reference to precombustion chambers)? I had assumed that all the engines were direct injection after reading various other comments re starting and lack of real need for glow plugs probably mostly relating to the 1HD-T engine.

This being the case then Beno's suggested causes are both possible.

Was it definitely coolant or could it have been condensation?

Just a thought.

 

[Beno]

Excuse my ignorance here but are the 1hz engines indirect injection (reference to precombustion chambers)? I had assumed that all the engines were direct injection after reading various other comments re starting and lack of real need for glow plugs probably mostly relating to the 1HD-T engine.

This being the case then Beno's suggested causes are both possible.

Was it definitely coolant or could it have been condensation?

Just a thought.

Hey Starcruiser

Yes the 1HZ motor is indirect injection as is the 2 h motor.
The 1HD-T and the 1HD-FT and the 1HDFTE motors are all direct injection and also all factory turbo charged. Even the factory Turbo motors all have glow plugs fitted.
Another thing to note is that the factory turbo motors usually have a lower compression ratio. The indirect 1HZ was up around 22 to 1 where as the factory motors were a bit lower around around 18 to 1 from memory. The lower compression ratio in the Turbo motor is to accomdate the turbo boost when it comes on.

When you add a after market turbo to a 1hz you have to be a bit more careful and make sure your injectors and pump are right up to spec to make sure you get good fuel atomization and a good clean burn. Bad or dribbling injectors will in the end leed to cracked pistons in the 1HZ. The pistons in the 80 series 1HZ are bit more heavy duty and can take the after market turbo a bit more than the pistons in the HZJ105.

Hope this helps.

 

[StarCruiser]

Thanks Beno, I'm still adding to my knowledge banks on these vehicles so appreciate the info. I suspected the compression ratios would be different for turbo against non turbo and have rebuilt a small Kubota diesel that is known for cracking around combustion chambers in the thermo siphon cooled version.

Speaking of injectors and pump (and promising not to continue hijacking this thread) is the eye stinging exhaust that points to injectors needing a service something that causes future problems on the 1HD-T?

 

[Beno]

To be honest i am not sure what you mean by eye stinging exhaust. I won't go off topic suffice to say that any injectors that start to become faulty will have a greater detrimental affect on a Indirect Injection where as the Direct Injection motors have pistons that are designed to take alot more heat stress. A faulty injector will cause hot spots in pistons and cracking and also worse fuel economy and less k/w and N/M.

With regards to to the OP saying the motor is back together and fine and running as it should is also quite possible. I have read on other Forums that the head on the 1HZ can have cracks in and around the precombustion chambers and still run fine for years and years and do thousands and thousands of kilometres with out a problem. Hopefully that is the case with the OP,S Cruiser.

 

[Crackity]

With regards to to the OP saying the motor is back together and fine and running as it should is also quite possible. I have read on other Forums that the head on the 1HZ can have cracks in and around the precombustion chambers and still run fine for years and years and do thousands and thousands of kilometres with out a problem. Hopefully that is the case with the OP,S Cruiser.[/QUOTE]

Yeah that makes the most sense to me. As it was running fine before I pulled out the bearings and it's running fine again now. And yes it was definitely coolant dripping down - bright green! However it's not the sort of problem you want niggling away in the back of your head in the middle of nowhere. Guess I'm setting aside some time and funds to pull the head off. Thanks Beno, you obviously know these engines back to front.

 

[Crackity]

Actually, one thing I have noticed more recently, and it's what lead me to do the BEBs in the first place, is a slight increased "rattling" on start up - like an exaggeration of the standard diesel combustion noise, but it goes away after 30 seconds or so. Could this factor into the injector/pump/piston equation?
It does still have me stumped though, why there was no evidence of coolant at all when I first removed the sump, or for two days after that. It was only the third day that the coolant appeared.

 

[Beno]

No problem mate try to help where i can.

i have found Lcool is very informative. There is a thread on LCOOL dedicated to whether or not to turbo charge the 1HZ.

Have a read if you are interested.
http://www.lcool.org/forum/viewtopic.php?t=19106

I had a HZJ 105 with a turbo and intercooler and bigger exhaust. It went well BUT. I upgraded to the VDJ200R it goes a whole lot better.

 

[frank rabbets]

In UK, at least. The 1-HD and 1HD-FTE do not have glow plugs.

 

[Beno]

In UK, at least. The 1-HD and 1HD-FTE do not have glow plugs.

Yes that is correct they do not have glow plugs.Apologies. The 1hdfte motor and the hd-ft motor both have Heater screens. The 1HD-T does still have glow plugs.

 

[Dave2000]

Actually, one thing I have noticed more recently, and it's what lead me to do the BEBs in the first place, is a slight increased "rattling" on start up - like an exaggeration of the standard diesel combustion noise, but it goes away after 30 seconds or so.

This could be seepage of coolant into the combustion chamber, if you imagine a thin layer of water on the piston crown,this will increase compression as water is not compressible. It could be the few seconds rattle is actually pre ignition or the coolant is cooling that particular chamber preventing it firing until the water has been blown out the exhaust. Might be worth getting someone to start the car after standing overnight while you watch the exhaust to see if there is a particularly smoky period whilst the rattle is taking place?

The period of time taken to show the leak is possibly because there are depressions on the piston crown that needed to fill and then over spill or, the water was working it's way around the piston rings, then dropping through the ring gap (biggest when cold) down onto the next ring and so on until the leak showed.

regards

Dave