Is this an overheating problem?

[grayham]

1989 Maestro Tandy Diesel 2.0
My Tandy gets very little use in the winter other than a once a week round trip of about 15 miles.
When I did the trip last night after about 5 miles there was a lot of fumes and I found the oil filler cap had blown off and there was a spray of oil everywhere on the engine. This is the second time this has happened.
Also when I got home the radiator was spraying water out.
The temp guage only went to a middle reading.
Last summer we didn't have a problem except for the occasional very fine spray of water which radweld put right. I have never heard/ seen the fan kick in.

Could the engine overheat causing the oil pressure in the filler tube to blow the cap off on such a short run ? Can anyone suggest a probable cause ?
It has done under 72k from new ( I have all the paperwork from new) and has been regularly serviced.
Can anyone advise what to check out.
Thanks in anticipation.
grayham

[MG MAL]

Graham,
The first thing i would do, is go back to the camper and fire it up.
Remove the oil filler cap, and if you are getting "pulse's" of air pressure coming up thru the oil filler pipe, then it would suggest that either a piston has gone, or a set of rings have failed, allowing excess sump pressure which is exiting from the oil filler tube.

My TD estate did this when it "holed" no.3 piston.

Also, if this has happened and it has damaged the head gasket in the process, some of the excess pressure will escape thru the cooling system causing the expansion tank to release the pressure at the cap(hence the spray of coolent.

This is not a 'Terminal' ailment for a diesel, as the blocks are very well built, but it may cause excess corrosion to the cylinder head if not repaired soonest.

I'm sure that Dan(E_T_V) can explain better on this subject as he has recently carried out two cylinder head gasker replacment's recently.

Mal.

[E_T_V]

It is unusual for the oil cap to be blown off, although there is usually some positive pressure in the crank case. One thing you might like to try is to start the engine from cold take it a mile or so up the road so the engine is ust warm but not hot and then try squeezing the large rubber coolant hoses. If they are very firm and hard and the coolant isn't boiling hot then I'm afraid it probably isn't good news. (But it isn't too bad either!). The other thing to look at is to start the car and remove the expansion tank lid and look for bubbles in there. If there is a constant stream then it may well have suffered the same problems as many diesels of this age (head gasket failure) particularly if the antifreeze hasn't been changed regularly in its life. Also check the colour of the oil. It'll probably be black which is fine but if it has a mayonaise type consistancy then again water may be present in the oil indicating a possible head gasket failure. Don't worry unduely though, these engines are tough and I ran mine with a duff headgasket for 3 months before I got round to fixing it!

However it may be somethign much more simple such as a faulty coolant temperature sensor or a faulty fan sensor. As the car gets so little use in winter it may also be blocked oil breather pipes.

To test to see if the fan works if you look at the drivers side of the radiator you'll see a little electrical connector with two connectors attaching to a sensor in the radiator. Pull these connectors off and then insert a piece of wire into the wiring plug so joining the two connectors together. (Do this with the ignition switch off). Then turn the ignition on. The fan should now operate. If it doesn't then turn the igntion off, remove the grill (two screws on the bonnet catch area), then you'll be able to see the fan. Try turning it by hand. It should be fairly free to move not stiff (which they often are). Spin it by hand a few times to free it up, (adding a few drops of oil to the spindle in the centre often helps). Then open the fuse box under the steering wheel and replace the cooling fan fuse (15 amp I think). What usually happens is the diesel uses the fan so little that it seizes up with lack of use then when it is needed the fan is so stiff that is blows the fuse leading to overheating problems. When the fuse is replaced turn the ignition on again and hopefully now the fan should work correctly. If it doesn't then we'll have to investigate some more.

As for the oil breathers check that the oil is not looking a bit like mayonaise (stiff and slightly milky to look at), then if thats ok remove the hoses from the front of the engine and check that they are clear and not blocked up with gunge. Blocked breather pipes was common on 1.6 models but not on the diesels. There is a small metal "mushroom" shaped thing next to the oil filler which should be clamped tightly on (if not oil gets everywhere!). This I think controls the pressure in the crank case and it is possible that this is faulty or blocked up with more gunge.

Anyway that is enough of my drivel for now. Let us know how you get on.

[grayham]

Thanks to you both for your quick reply and suggestiions.
Took it for a short run as suggested and felt the pipes. they were not hard and there were no bubbles in the expansion tank.
Left the engine running for a time and still the pipes were not hard and no bubbles.
Removed the cloth I had to use to replace the oil filler cap and there was some oil fumes but not much and there is some pulsing. At first I thought there was virtually no presssure behind it as I could put my hand over it and could not feel any force behind it, but then I removed the mushroom and blocked that outlet and there is pressure.
The fan had not cut in but I am not sure ifit was hot enough to trigger it but used a bit of wire as suggested and the fan does work fine.
The oil shows no sign of any milkiness and there does not appear to be any moisture in the fumes.
The breather pipes seem OK and not obstructed, not sure what the mushroom thing does but it seems clear.
When I come home from work I will take it for a longer run ( or do a repeat of last nights trip) and see what happens paying particular attention to the fan and hoses.
It may well be that I had not put the oil filler cap on hard enough and it shook loose but as it has happened twice ........................
While checking the fan I can see that the radiator has several bad/corroded places and is wet so the radweld has not solved that problem.
So does all this indicate that the problem is overheating , blown gasket or can you suggest something else to check for?
My thanks to you both for all your help.
grayham

[E_T_V]

While checking the fan I can see that the radiator has several bad/corroded places and is wet so the radweld has not solved that problem.
So does all this indicate that the problem is overheating , blown gasket or can you suggest something else to check for?
My thanks to you both for all your help.
grayham

Yes the radiator is certainly an area to look at. It is possible that the radweld has blocked up the radiator causing it to overheat (but this is a bit unlikely). I think there are a few suitable new radiators on e-bay at the moment if that is any use, (they are easy enough to change).

The pressure and regular pulsing is fairly normal, (initially if you put your hand over the oil filler pipe you'll feel virutally no pressure but after 5 seconds or so the pressure builds up and you have to be careful not to squirt yourself with oil mist when you remove your hand!

I think the "mushroom" thing acts as a safety valve and vents excess pressure back into the inlet tract. If this is blocked or defective then that could cause you problems however I'm not really sure as to how you could test this other than to replace it with another one.

If the pressure pulses are irregular (i.e. puff, PUFF, puff, PUFF,.....) or it seems to chuff like a steam train then you may have a defective piston/ring, but I'm fairly sure yours will be ok.

I'd not worry about the fan not coming on so long as it works properly as the diesel never seems to need the extra cooling, (most people have difficulty making them run hot enough to make the heater work!).

My advice would be to change the radiator before it lets you down, (cheap ones on e-bay will do the job), at the same time flushing the cooling system to clear out any rust and dirt, (see the FAQ on how to make your heater hotter), and then try and get hold of a new/used "mushroom" piece to see if that helps. I'm not sure how to explain the water boiling. Did you overfill the expansion tank by any chance? (it should ony be filled when cold so that the coolant just covers the "finger" protruding from the bottom of the tank. If you overfill it then the water is forced out as the water expands as it is heated by the engine.

If you need any bits then please ask as people are usually very helpful in finding needed stuff.

[MG MAL]

Thank's Dan,
I knew you would be able to clarify things for Graham.

Is'nt there still the possability that the head gasket is on its way out, but as yet the breach is too small, and / or exhaust gas pressure to high to allow the coolent to mix with the oil?.

I don't want to put the willy's up Graham by making him think that it's worse than it actually is, but i always found if everything else is ok(coolent system wise) then it is a sure sign of H/G failure on its way?


Mal.

[E_T_V]

It could be a sign that the headgasket is on the way out however it is usually the water pipes that get pressurised before the oil does, and if they pipes aren't pressurised even when the engine is warm and it has been regularly serviced (I'm assuming this also means regular antifreeze changes), then it seems a bit odd that it would have head gasket failure after such a low milage with no oil leaks to the outside of the block being present.
The corroded radiator may point to a lack of antifreeze maintainance but seeing as both mine and tonys were also bad at a younger age (J, L and M reg), then it may be a false alarm.

When I get home I'll try and dig out the pics of the headgasket failure and show why I don't think it will be leaking from the cylinder into the oil ways without contaminating the coolant or causing lots of blue smoke!

Two final checks are to remove the expansion tank with the engine running and warmed up. Do this slowly to release the pressure. Then replace the cap for 30 seconds or so with the engine still running and then remove it again. If you can hear pressure being released then you may have combustion gases being released into your coolant (as the gases released must have come from somewhere). The last is to dip your finger in the expansion tank when it is cool and then rub your fingers together. If it is slimey or greasy then you may have a head gasket problem.
Also if the coolant smells "burnt" or of diesel fumes then again the head gasket is suspect.

The usual progression of headgasket failure in order of severity seems to be
1. Combustion gases leak into coolant
2. Coolant leaks into cylinder
3. Coolant mixes with oil

However it may just be a clogged coolant system and a faulty crank case pressure valve. Oh yes that just reminded me. The breather hose from that valve leads to the air filter housing, it may be worth checking that it isn't kinked anywhere along its length as if I rememember mine is quite long and bends up to the bottom of the air filter housing out of sight so it may be easily missed.

[grayham]

You are both fantastic!! :beer:
Many thanks for all your suggestions.
I will flush the cooling system to clear out any rust and dirt and see what condition the coolant is and look out for a new radiator (oh and a new oil filler cap , maybe 2 just in case.)
I am obviously hoping that it is not a head gasket or anything too serious.
BTW I had already checked the breather tube to the air filter and that was fine.
I will take it for a run later and see what happens.
Once again my thanks
grayham
(with a Y as I see there is another graham on the list)

[Jack]

The Haynes manual states how to test the mushroom thingy. I think you need some way of applying a vacuum though.

Whenever I have had problems like this I find it always pays to sort out what is obviously wrong, even if you can't understand why it might be causing the symptoms you describe. In other words, change the radiator and flush the pipes and block through.

I would have thought crankcase breather hoses being blocked might increase crankcase pressure and push out the oil filler cap. If well maintained, you've got a Friday afternoon engine if it's a blown gasket at that mileage surely?

[grayham]

Well, I took the van out and did a run of 18 miles with just one stop after 13 miles.
The hoses were not hard , there was no smoke and no leaking from the radiator.
The fan did not come on.

I don't think that my probing dislodged any blockage so what do I do now?????????????

The radiator will be replaced as soon as I get one.

[E_T_V]

I'm a bit stumped as to what it can be. To check the PCV valve disconnect the vacuum hose from it and apply suction to this hose. If you can hear it clicking then apprently according to the haynes manual it is working correctly.

Is the oil filler cap a tight fit? I'm not sure if there is a giant rubber O ring on the end of the filler cap or not but the cap should be a fairly tight fit on the filler pipe. Also is the van using any water? If you aren't getting pressure in the rubber pipes (and the expansion tank is actually sealing properly), then that is a good sign. When yoiu change the coolant and flush the system when you replace the radiator make sure you replace the antifreeze.

If it transpires that your head gasket has started to leak then my advice is simple. loosen the expansion tank cap and unless you are unlucky you should be fine for weeks to come. (just keep a keen eye on the temperature gauge and coolant and oil level. If oil starts mixing with the water and vice versa then stop.

I'm not sure what else it can be.. If you overfilled either the oil or water levels then this could explain the excess pressure you've observed in either system. Is the oil level normal and the water level around the "finger" sticking up from the bottom of the coolant tank?

[grayham]

I'm a bit stumped as to what it can be. To check the PCV valve disconnect the vacuum hose from it and apply suction to this hose. If you can hear it clicking then apprently according to the haynes manual it is working correctly.

UMMMMM What is the PCV valve?

Is the oil filler cap a tight fit? I'm not sure if there is a giant rubber O ring on the end of the filler cap or not but the cap should be a fairly tight fit on the filler pipe.
The oil filler cap was lost last night. At the moment I have a cloth stuffed in the pipe. (Please don't shout at me ........... cant find an emoticon of hide my face in shame!!)

If you overfilled either the oil or water levels then this could explain the excess pressure you've observed in either system. Is the oil level normal and the water level around the "finger" sticking up from the bottom of the coolant tank?
I am pretty certain that the levels were OK when I left.

Once again many thanks for all your assistance, without it I wouldn't have had a clue where to start looking.
Hopefully it will not happen again but I will watch it for a while.
Many thanks
Grayham

[E_T_V]

Hmm interesting. The PCV valve is the small metal mushroom shaped thing that sits next to the oil filler pipe. Basically from what I can work out it is there to regulate the crankcase pressure and allow excess fumes to pass back into the air inlet to be re-burnt. If you need an oil filler cap I think I've got one on my old engine which you can have if you want. It might be an idea to drill a small hole around the edge of it to secure it to the engine with wire/cable tie etc so that it can't go missing again! If you can find a local car breakers yard I'd try to find a maestro or montego diesel or turbo diesel and get the cap and PCV valve from that.

Are you losing any oil or water or is the exhaust smoke blue or very steamy?

[grayham]

If you need an oil filler cap I think I've got one on my old engine which you can have if you want. It might be an idea to drill a small hole around the edge of it to secure it to the engine with wire/cable tie etc so that it can't go missing again!
I took you up on your offer and it was received this morning!! Many thanks for that. Please let me at least cover cost of postage.

If you can find a local car breakers yard I'd try to find a maestro or montego diesel or turbo diesel and get the cap and PCV valve from that.

I have phoned every yard in a 15 mile radius and there is not one Maestro/Montego being broken nor do they keep the parts I need.

As the MOT is due I decided reluctantly that the best thing is for the garage to look into it all. Unfortunately at the moment I do not have the time to do much and it is essential that I am mobile.

I am very grateful to you all for your assistance. Best wishes and I hope to meet up with you at sometime.
Grayham

[E_T_V]

The postage was the grand sum of 30p so I don't think there is much point writing a cheque for that! Buy me a drink when you see me at an event sometime and that'll be fine.

Hopefully it may have just been a case of the O-ring on your old cap had gone missing so it wasn't a tight fit in the filler neck. Unfortunatly I don't have a space PCV valve (well a working spare that is!). I hope the garage find that it is something fairly easy to fix/replace. If bits are needed then put up a wanted here and I'm sure someone will be able to help

[grayham]

The postage was the grand sum of 30p so I don't think there is much point writing a cheque for that! Buy me a drink when you see me at an event sometime and that'll be fine. :beer:

Many thanks

Hopefully it may have just been a case of the O-ring on your old cap had gone missing so it wasn't a tight fit in the filler neck. Unfortunatly I don't have a space PCV valve (well a working spare that is!). I hope the garage find that it is something fairly easy to fix/replace. If bits are needed then put up a wanted here and I'm sure someone will be able to help
Just got the van back with a new MOT ;) ;) ;)
2 new heater plugs and a little welding on the sill and 2 shocks , well 3 shocks if you count the bill!
I think you may well be right about the O ring being missing on the old cap, have just fitted the one you sent which was far, far harder to push down than I remember the previous one was. (Did drill a little hole and attach a cord to it !)
He checked the PCV valve and said it was OK.
It definately needs a new rad which is being fitted on Monday and he will do an oil change at the same time. (yet another bill :worried: )
Hopefully that will be the end of the troubles , at least til the next time.

Grayham
with a Y

[darrenandsarah]

It definately needs a new rad which is being fitted on Monday and he will do an oil change at the same time. (yet another bill :worried: )



You could always fit the rad yourself, I would consider myself a novice at car maintenance and won't attempt anything over two spanners in the haynes manual, but I have done a couple of radiators on my monty TDs and they are dead easy, remove a bit of the trim from the grill and a couple of hoses have a squirt around with a hose if you want, bang the new one in with antifreeze etc and squeeze a few pipes, that's just about it and if I can do it anyone can.

[grayham]

You could always fit the rad yourself, I would consider myself a novice at car maintenance and won't attempt anything over two spanners in the haynes manual, but I have done a couple of radiators on my monty TDs and they are dead easy, remove a bit of the trim from the grill and a couple of hoses have a squirt around with a hose if you want, bang the new one in with antifreeze etc and squeeze a few pipes, that's just about it and if I can do it anyone can.


Thanks for your reply.
You sound much the same as me on mechanics.You claim to be a novice at car maintenance , well that puts you 3 grades ahead of me :hat:
Unfortunately time is against me at the moment as we have a few days away at the end of next week and I have to catch up with myself at work. Infact I have to overtake myself and make sure that I can have the time off.
( I am writing this from work :( :( )
Any extra money I earn looks like it is going to pay for the van.
At least the van will be done.
Ah well back to the grindstone

itsalarfinit !!!
Grayham
with a y