1,6TD JX Possible HEAD work

[epowell]

I MIGHT have a problem with my HEAD. I will know for sure in about a week when the van is back together after a RAD. cleaning etc. etc.

I was having serious over-heating problems and cold RAD., but found no blockages in the cooling system whatsoever...   So I suspect maybe an internally leaking head gasket.

In one week my van will be together again with 100% new coolant and heater pipes/hoses and re-conditioned RAD. - so by then if it is still overheating, I think it might be the head gasket or worse...

The other issue is that I have a time crunch - I have 2 months to prepare for the State Technical Control, and PLENTY of other things to fix on the van > keeping in mind I am a relative newby. I am good at getting things done but I need time to study and learn as I go.

So my question is this: If I do find that I need to change the HEAD GASKET, then obviously it would make a lot of sense to do some other things on the head (valves etc) at the same time, no? May I ask, what are those other things that I should do and how long can such work take?

The reason I ask now is so that I can begin now to study up on the possible work - research, familiarize myself, source needed parts and tools - all of which will greatly speed up any work that I might have to do.

Big thanks!
Edward

[RunninWild]

You say the rad was cold? Did you look at the thermostat? If it's stuck closed it won't let coolant enter the rad and the engine will overheat almost instantly.

Are you loosing coolant? Does your oil look like yellow/green sludge? Excessive smoke from the exhaust? Is your coolant contaminated with oil?

Honestly your problem sounds more like a bad thermostat then a head gasket but you've left out a lot of information for anyone to make an educated guess.

[epowell]

You say the rad was cold? Did you look at the thermostat? If it's stuck closed it won't let coolant enter the rad and the engine will overheat almost instantly.

Are you loosing coolant? Does your oil look like yellow/green sludge? Excessive smoke from the exhaust? Is your coolant contaminated with oil?

Honestly your problem sounds more like a bad thermostat then a head gasket but you've left out a lot of information for anyone to make an educated guess.

Sorry, I was asking more about what a typical HEAD reconditioning entails...  but now that you mention about the overheating, I will fill you in (and by the way I HOPE my head is OK!!! )

I don't notice any head leaking or coolant in the oil (but have not looked really carefully yet).

Basically the van was overheating and found that the RAD was stone cold...  I opened the cooling system and found NO blockages in the pipes or rad itself. Next I removed the thermostat and put it in boiling water and it opened normally....      so what can it be?

Another weird thing is that when the engine was overheating, the cabin heater was not giving much heat!    so?

In any case, in a few days it will all be back together and I will know more...  I hope it is not the head, but if it is I better start studying now.

- - -
I have the VAG JX manual and in that is talks about these tasks:
1) REWORKING VALVE SEATS
2) RENEWING GUIDES
3) RENEWING VALVE STEM SEALS

...does this about cover it?   Considering that last year I did these things:
1) REPLACED CAM OIL SEAL
2) SET VALVE LASH

[RunninWild]

Cold rad and no heat probably means you were low on coolant or have an air bubble stuck in the system somewhere.

[epowell]

Yeah exactly...  I THOUGHT that the coolant level was OK because it looked that way from  the coolant tank... BUT if there was a big bubble somewhere then that would displace coolant thereby making the tank level appear normal.

I discovered this problem after not driving the van for 7 weeks...  I had a couple of coolant leaks so likely that air could have been getting in that way.

I hope this is it only!

[libbydiesel]

When you get it back together you will need to bleed the cooling system well.  The 'libby bong' makes it easier, less messy, and less stressful than the method recommended in the Bentley.  After getting it bled, run it up to temp, park with the passenger front raised a little and open the radiator bleeder.  Let any air hiss out until coolant come out.  Do some more driving, park with that side up and repeat.  Do that until only coolant comes out. 

If you continue to have overheating issues, then the head gasket is certainly a possibility.  You would want to inspect the head first for cracks.  Small cracks right between the valve seats of each cylinder are normal.  Cracks on the combustion face running toward the pre-combustion chambers are not uncommon and render the head unusable/un-rebuildable.  It is also quite common for there to be small cracks in the pr-combustion chamber inserts.  You cannot actually tell if the inserts are cracked unless you buff them to a shine.  Those little cracks can sometimes grow very quickly.  If the pre-chamber cracks into two pieces, the piece or pieces will fall out of place and into the cylinder causing major damage.  If inserts are not cracked and the casting between the inserts and valve seats are not cracked, then usually the head can be refreshed with a valve job.  You would want to have a local machine shop do the work.  I'd make sure it is someone who is familiar with the older VW diesels. 

[epowell]

  Those little cracks can sometimes grow very quickly.  If the pre-chamber cracks into two pieces, the piece or pieces will fall out of place and into the cylinder causing major damage. 

I am concerned about this possibility because the over-heating issue manifested in a peculiar kind of EXPONENTIALLY INCREASING sort of way. Before my 6 week trip I did in fact notice the tendency in a very subtle way (the van was slightly over heating when driving slow or idling and cooled down when driving fast -- keep in mind my fan was not working at all).
Then after the 6 week trip this tendency was there again but a bit more pronounced...  next day I tightened the alt.belt and the tendency was even more...  next day I wired up a dash switch for the fan to run the fan and the tendency was starting to get serious...  next day I only drove for 3 minutes and the needle almost went thru the roof!

My fear is that this might be an internal head crack which is now growing really fast and can threaten to seriously damage the engine.

I am tempted to pull the head now and not risk starting her up again >>> but probably what I will do is start her up and if overheating again, then IMMEDIATELY shut her down. I won't go for a drive unless I can run the engine for 15 minutes or so without any sign of overheating.

Another thing...... right now I have the nose of the van MAJORLY jacked up in order to do  front end work. Wouldn't it be a good idea to keep the van jacked up in this way to do the bleeding?

[libbydiesel]

Although a crack leading to the cooling system could cause 'overheating' that wasn't specifically why I mentioned that.  I mentioned it in order to give examples of issues you might face that might cause the head to be un-rebuildable.

What were your symptoms of overheating?  Did you experience boiling of coolant?  Did the needle peg?  Light flash? 

[epowell]

What were your symptoms of overheating?  Did you experience boiling of coolant?  Did the needle peg?  Light flash?

The ONLY "symptoms" of over-heating I experienced were based entirely on the needle, nothing else. I did notice that the cabin heat was not particularly strong which leaves me to also contemplate the possibility that in fact my engine was NOT overheating. When I did these tests the outside temps were VERY low and I was NOT pushing the van hardly at all > so the low cabin heat would correspond to what the cabin heat normally would do if the engine was not particularly hot.

...so could it simply be that for some reason my needle has become hypersensitive?  Is this possible, common? It is the only thing that fully explains everything.

Regarding that needle > it was not even hooked up before Mark's visit last May...  he noticed this and wired up for me a TEMPORARY connection from the dash to the engine with some cheap old speaker wire....   I am embarrassed to say that I just left it in there since it was working well. Maybe this questionable wire is the issue > probably time to replace it with a brand new wire.

[RunninWild]

Get a digital heat gun and confirm its overheating. Your gauge sounds iffy and there's no point in replacing parts until you know for sure you have an issue.

[epowell]

Get a digital heat gun and confirm its overheating. Your gauge sounds iffy and there's no point in replacing parts until you know for sure you have an issue.

haha...  bit too late for that, I just finished having the rad. refurbished, and replaced all old coolant and heater pipes/hoses...    no prob., those things probably should have been done anyway.
Let's hope the problem is just the temp guage and/or wire.....