Headers and pipe glowing red hot

[deepak Lurker Find all posts View Profile Close deepak]

Hi,

I have a 2004 prado 4.0 V6 petrol.

I experienced an engine failure and choose to have the repair done by an ex-toyota technician that recently started up his own workshop.

I now need advice/ direction because the said technician cannot diagnose and solve the problem.

This is my story ....
Engine overheated due to waterpump failure.
Started smoking ...white smoke.
Brown coolant sludge on oil cap.
Removed cyclinder heads.
Engineers pressure tested the heads ... no problem found.
Light skim and no warping of heads.
Replaced head gaskets.
Replaced radiator.
Replaced water pump.
Replace thermostat.
Problem now is that the technician now says that headers and pipe is glowing red hot on left side.
Technician says timing is set correct.
Also, removed pre-cat .... because technician suspected it was blocked.

Please advise on possible things that could be wrong before I tow away the vehicle and let the Toyota dealership try to diagnose the problem.

Thanks in advance.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Under what condition is it glowing?

Assuming under load, has the tech done an exhaust gas analyses to
confirm fuel mixture is correct, a lean mixture will cause the engine to
run hot, ie faulty fuel injector.

Also as the head was removed, are they sure the cam timing is correct?

Cheers

LeighW

[deepak Lurker Find all posts View Profile Close deepak]

Hi Leigh,

Vehicle is not being driven ..... was only started and run for ten minutes for glowing to occur.

Technician said previously that the fuel/air mixture was not touched during the head removal.
No exhaust gas analysis has been done.

Technician is adamant that timing is correct ... says it as per Toyota specs.

Thanks,
Regards,
Deepak

[timmay5.7 Advanced Member Find all posts View Profile Close timmay5.7]

Get him to pay for it to be hooked up to a diagnosis machine and check for fault codes.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

He may not have touched the fuel mixture but the over heating and or incorrect
re assembly may have damaged something.

If the headers are glowing whislt idling you have a serious issue, is the motor running
smoothly while idling, does it rev ok. If miss firing you can get serious temperatures in
the exhaust manifold due to fuel burning in the manifold and not in the cylinder. Also
still would suspect a mixture, ignition timing, valve timing or valve clearance problem.

If all above is ok check that there is coolant in the cylinder head and that it is being circulated properly.
ie check coolant system has been bleed of air properly.

Cheers
LeighW

[quadcam Junior Member Find all posts View Profile Close quadcam]

are they sure the cam timing is correct?

This gets my vote.

[KAKADAZ Avid PP Poster! Find all posts View Profile Close KAKADAZ]

It does sound like it's passing out gasses that are still burning (valve timing) or an exhaust or blocked cat converter but if he's checked that then it must be timing.

[tassie tiger Advanced Member Find all posts View Profile Close tassie tiger]

I wonder if it really was waterpump failure and not something else. Waterpumps rarely fail its normally a belt that fails (sorry if incorrect)

I think its a fuel issue. If the timing is out then it should be running like a goat.

[deepak Lurker Find all posts View Profile Close deepak]

I have spoken to the tech once again.

The story has changed ... from the engine running smoothly ....to .... no power and a possible misfire as if something is blocked.

My "technician" is now enlisting the help of a senior toyota technician to help diagnose the problem ... he will come by on Saturday.

In my humble opinion, I think that the timing and the valve clearances are the two main problems.
However, I need to know how can I extract the results of this from the technicians in a concrete manner ...so that we can find a way forward from here.
Way forward being:
1. Remove heads again ..... send back to engineer for full valve job.
2. Send vehicle to Toyota so there can hook up their dianostic tools and resolve.
3. Just follow the advice of the senior technician and see what happens.

I am stressing now ..... time and money is all that seems to be going.

[raydes Advanced Member Find all posts View Profile Close raydes]

Cam timing gets my vote as well . Ask him if you can get someone else to check the timing ,, RAC RACV ect I don't think you are going to get the truth from him but you will get the BILL.

[tassie tiger Advanced Member Find all posts View Profile Close tassie tiger]

Take it to Toyota for diagnostic run. Otherwise you are just going to keep chasing your tail.

Modern engines are so technical that even good mechanics struggle to diagnose without all the gear and service bulletins.

Heres an example. Our Rav would occasionally just hesitate for no reason. Only Toyota were aware of the problem and only as it came out in a service bulletin. The answer was a reflash of the ecu. I could have spent weeks at a local place and never got it fixed.

Just to be a pain. How did you know it was waterpump failure - this needs to be sorted as you may well cook this new one of the actual cause is not diagnosed.
cheers

[quadcam Junior Member Find all posts View Profile Close quadcam]

Before the engine goes near any diagnostic machine some mechanical things need to be ascertained. Compression test and Leakdown test for EVERY cylinder. If those are in not in spec it is no use doing anything else.

[Billy Junior Member Find all posts View Profile Close Billy]

Started smoking ...white smoke.

.

This would suggest coolant has entered cyclinders

In dont know how hot the engine got but alot of times after an engine full Alloy engine has overheated a blown head gasket goes hand in hand with a warped head and somtimes even the block.

Check all the spark plugs(the part inside the combustion chamber) and see if there is difference in colour between both banks ,especially between the cylinder bank closest to the glowing exhaust side.This would certainly narrow the problem down especially if one or two plugs where different on the problem cylinder bank side.

I dont think the spark timing can be ajusted without changing the ECU settings(im not sure if it can be changed all!)

Checking the valve timing shoulded be that much of a job for an ex toyota mechanic

I hope this helps

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

Curious to know how many klms your prado has on it ?? I havnt heard of water pump failure on the 120 V6 (well anything under 200k anyway) White smoke I have seen this twice, first was water/coolant entering the engine, the second was my old mans Datsun, and it was to do with the auto transmission, I was only young then so have no idea how the auto transmission would have an effect on the engine but some thing to do with auto fluid getting into engine ?? no idea how ?? Been quad cam maybe he hasnt ligned the cams up correctly, I have never done one (and dont intend to) but would imagine that it would take a while to line up all four into correct timing alignment ?? Have you redone a coolant pressure check ?? to make sure its not pressurising anything ?? Can be cracked and not be using water but exhaust gases escaping ?? As said above I would be checking as to why it over heated in the first place, Im not convined it was water pump totally, unless you have extremely high klms or your just unlucky as I havnt heard of this been an issue with the 120 V6. If it got that hot Im extremely suprised it didnt warp a head or the block for that matter been all alloy engine, cast iron probably get away with it getting hot. I will ask my mate also an ex Toyota head mechanic for 20 years seen if he can enlighten the issue Cheers Steve

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

Just thought of how the transmission fluid would have got into engine, would imagine it would have been through the transmission lines going into radiator and possibly the cooler in the bottom had split or some thing so it mixed with coolant ?? Dont remember him having any issues with the auto which would be suprising if he didnt unless it only pump the fluid one way and didnt get back to box??????? Cheers Steve