7,000 kms on a rebuilt toyota 2.8 diesel - update

[nzlux]

I had my hilux 3L (2.8 na diesel engine) reconditioned 7,000 kms ago, bore and hone, block surface grind, new pistons, rings, bearings, thrust set, spigot bearing, head gasket, cam belt, front housing and oil pump and a new head, plus a new radiator ouch!!!!

I asked about the need to have the head torqued after driving and was told the bolts used meant this wasn't necessary.

Within a fortnight the radiator drank ½ a litre of oil (engine oil dropped and oil appeared under the radiator cap) topped up the oil, had the radiator flushed and contacted the shop that did the work. On the trip to and from town it did not loose any more oil.

He scratched his head and said maybe the oil cooler but that would be doing it all the time not just now and then or a cracked engine block and to keep an eye on it and let him know if it did it again.

It didn't do it again, until a couple of months later when I went on 800 km road trip, Whangarei, Hamilton, Tauranga, Whangarei, and yes it did it again.
It seemed now to do it on long trips but not on the 50km return trip to work each day.

Today I checked the oil and coolant, I do it weekly, oil is still near the top of the dipstick, so it has used a little, and there was some oil on the radiator cap, of more concern the overflow bottle was empty and the radiator down about a litre of coolant, no signs of coolant under the vehicle either, there is plenty of water about in Northland but no green stuff on my garage floor.

The oil is black, i.e. not milky, as it was at 5,000km when I gave it an oil change and new filter (I did ask if it needed to be changed earlier, and was told 5,000km after rebuild was fine).

The engine had not been using any coolant since the rebuilt, and has not got hot, I drive with an eye on the gauges, yes it is the factory gauge but it has not moved to ½ let alone above that.

I also noticed the radiator did have a burnt fuel type smell.

From my google research I'm picking it is a head gasket failure.

Any thoughts on:

1. Are there a type of head stud / bolt that does not need to be retorqued after 1,000km?

2. What is causing the above issues a crack in the engine block / hole in oil cooler / crack in head / faulty head gasket / other?

[imsohi]

I have replaced many heads and never retorqued the head bolts other than the initial one have done both 2lte and 1kz motors

[nzlux]

I have replaced many heads and never retorqued the head bolts other than the initial one have done both 2lte and 1kz motors

The guy who did the work did know what he was doing, and was not the cheapest in town.

Do you think the issue is with the head / gasket or the block?

I would have though it there was an issue with the block I would see coolant in the oil, and I havent.

[slide]

Torque to yield, 'stretch' bolts don't need, and can't be re-torqued.
Oil pressure ~100psi, coolant ~15psi- you can see why a leaking oil cooler can leak oil into coolant but not coolant into the oil. Not saying it is that, because it needs correct diagnosis.
I suggest taking it back to the crowd you got to do it, politely (but showing your disappointment) discuss issue with them and get them to test it out and hopefully rectify the problem for you (I guess that also depends on the original transaction)

[nzlux]

I has the same thoughts re differing pressures, but once the engine is turned off wouldn't the oil pressure drop to 0psi quicker than the coolant pressure?

That being the case the gap / crack / that the oil was getting though must be very small.
Now that coolant is vanishing possibly a new gap / crack?


I will take it back on Monday, it is a one man shop but he seems pretty straight so Im not expecting any problems.

Just wanted opinions from here as to what could be the problem.

[Crash bandicoot]

I was told when rebuilding my 2.4 to torque the head bolts
to f.t.......farkn tight. I ended up doing them per the instructions then cranking them till they creaked like an old rusty gate hinge, id say if this is the case with yours take it back and request the rebuilder fixes the situation or buy a new head gasket and torque the bolts down yourself.

[cornflake]

sounds like head gasket failure

[Mr Revhead]

Torque to yield, 'stretch' bolts don't need, and can't be re-torqued.

Spot on. So DO NOT "re torque" torque to yield bolts. Or they will yield too much...

But did they use new bolts? If not, did they measure the old ones to ensure they were still in spec? Going by the amount of work you had done, a set of new bolts would not have increased the cost by much.

[slide]

I was told when rebuilding my 2.4 to torque the head bolts
to f.t.......farkn tight. I ended up doing them per the instructions then cranking them till they creaked like an old rusty gate hinge,

WTF? This has to be some of the worst advice ever posted on this forum?
Why would you even post up that rubbish?

I has the same thoughts re differing pressures, but once the engine is turned off wouldn't the oil pressure drop to 0psi quicker than the coolant pressure?

That being the case the gap / crack / that the oil was getting though must be very small.

Yes, it could have a tiny leak- like needs 100psi or so pressure difference to leak. So after engine shut off the coolant pressure isn't enough to make it leak. And normal oil pressure isn't even enough, only the absolute pressure peaks. Bear in mind it could well have two separate problems that you are seeing symptoms from and thinking is only one problem.

[madlux]

Is the New head genuine or Chinese? I just replaced a Chinese head on a 1kz that had only done 30,000kS

[nzlux]

Don't I feel like a fool.

Topped the radiator up and took my wife out for her birthday lunch, got some more coolant on the way home, was topping the radiator up with the engine running and my wife asks why green stuff is spraying under there.

It was coming out from the heater hose, next to the thermostat housing, and drying before hitting the ground, hence not coolant under the vehicle.

Hose off, a small hole by the hose clip, duck tape around the hose, then hose clip over and the leak has stopped, will go to ripco and get a new hose tomorrow.

[derk]

good shit mate but doesn't explain the oil you've found in the radiator, is that still happening?

[nzlux]

good shit mate but doesn't explain the oil you've found in the radiator, is that still happening?

That still is happening only on long trips, it seems to be when the vehicle is cruising at 100km/h , 2500rmp in top gear for long periods of time, the factory oil pressure gauge sits just to the right of the line, second from the right (about ¾) according to the owners manual this is in the normal range, but maybe the gauge / sender is faulty and the pressure is too high, he did put a new oil pump in during the reconditioning of the engine… might change from 14/40 to 10/30 oil next change and see if that helps.

[Crash bandicoot]

Slide. Said engine is still going 876,000 kms in a 2wd flat deck delivering farm supplies. You are right in saying its "rubbish".its a toyota. But doesn't avoid the fact that particular statement came from a toyota dealership mechanic....they might know something more then what "the book" says to do.

[nzlux]

Yes, it could have a tiny leak- like needs 100psi or so pressure difference to leak. So after engine shut off the coolant pressure isn't enough to make it leak. And normal oil pressure isn't even enough, only the absolute pressure peaks. Bear in mind it could well have two separate problems that you are seeing symptoms from and thinking is only one problem.

I think you might be correct.

The coolant was a leak in a heater hose.

The oil is a tiny hole that only plays up at high pressure, ie long periods at 2500 rmp (100km/h in 5th) when the oil pressure gauge is reading its highest.
I will go to a lower grade oil, currently 15w40, next oil change I will go to 10w30, increased flow but lower pressure and see if that resolves the issue.

[Mr Revhead]

Slide. Said engine is still going 876,000 kms in a 2wd flat deck delivering farm supplies. You are right in saying its "rubbish".its a toyota. But doesn't avoid the fact that particular statement came from a toyota dealership mechanic....they might know something more then what "the book" says to do.

You still get idiots at dealerships.
Hell, I worked at 2....

[ChurchurDan]

On the longer trips the oil will also be getting hotter and will be getting thinner which may be why it only leaks when driven for a long time.
If this is the case a lower weight oil will make it worse. The second number on the oil is the viscosity when hot the higher the number the thicker it is when hot.

[tweake]

On the longer trips the oil will also be getting hotter .........

depends a lot on driving style and roads.
a long time cruising on fairly flat roads oil temp will go down. give it heaps in hilly areas and oil temp goes way up quickly.

how much oil in the water? could be left overs from the engine build and its washed off the block ?
at 7000 km and one oil change i wouldn't worry to much at this stage. your going to burn a bit with ring settling in. now the water leak is sorted, put some load on it, give it heaps and make the rings bed in.

[mudtroll]

Is it manual or auto? I had a similar problem, turned out to be transmission fluid leaking from a tiny split in the cooling pipe in the bottom of the radiator.

[nzlux]

Its a manual, that rules out an auto transmission cooler doing this.

I had the radiator flushed 1,000km after the rebuilt (after it did it the first time) and it has put more oil in there once since.

Oil appears on the bottom of the radiator cap and it drops on the dipstick during the same trip and at no other time. It has only done it twice, Im quite certain it is not residual oil from the rebuild.

Last time it happened was driving to Hamilton from Whangarei, after Auckland that is all flat so the engine wasn't working hard.

It burnt oil, but did not dump it in the coolant before the rebuilt so it could be the new head / new head gasket, or the block / oil cooler might have developed a tiny crack during the rebuilt process.

Does anyone have any tricks on finding where the leak is, other than stripping the whole engine down again?

I'm almost tempted to put some mechanic in a can in it before my next long trip but have reservations as it could be snake oil that either does nothing or causes more problems than it cures.

[tweake]

start with the easiest.
the oil cooler is the most likely place. a bit of crap on the housing gasket or the two oil cooler gaskets. check the bolt tension on the cooler housing, maybe someone missed tightening up one.

[nzlux]

Update.
Took the hilux back to the shop, the owner / engineer mentioned he had just put a 2L head on an engine and the bolt near the front (where the oil comes up near the water jacket) bound up when going in so had to be machined so they could be torqued correctly. He could not remember whether he had done this with my 3L.

He took the rocker cover off, took those bolts out, machined them and put them back. He said they did not feel tight when he took them out.

Hopefully all fixed now, but will not know until I do a decent road trip…. now where to go?

[Mr Revhead]

Ah... I think you might have a problem. The probable reason for those bolts not feeling right is they have stretched. Meaning they will not hold torque.
Machining them (I assume he just ran a thread die over them) and putting them back in is just asking for a broken bolt, blown headgasket or both

Toyota head bolts (torque to yield) must be replaced if not in spec

[zed]

A set of new head bolts is very cheap in comparison to the cost of a head or motor job. Always buy new torque to yeild headbolts and make sure the threads in the block are perfectly clear.

[nzlux]

The machining wasn't to do with the tread more to do with clearances, I didn't fully he what he did but he has committed to fixing the problem at no cost to me.
He has a set of new Toyota head bolts at his shop that he did not use.
As he is the engineer I will leave it up to him to get the recondition sorted.