Head Gasket or New Rad???

Adam · Post by **Adam** » Fri Aug 25, 2006 4:29 pm

Hi Guys, got a problem with the TZD, I've done all the usual things associated with buying a turbo diesel, thermostat, engine/coolant flush, back flush of the radiator, fan switch, bottom hose etc and i've still got a pronlem, the coolant is almost fizzing like it's carbonated, there is no obvious smell of spent fuel in the coolant and no water in the oil, oil in the water etc, power is good and the car runs fine but hot or cold and randomly all the coolant is pushed out of the expansion tank with the cap on (the coolant bubbles most of the time when the cap is off). It only overheats when the coolant is pushed out. Bleeding fom the thermostat drops the level in the tank back to normal.

Anyone experienced this? I'm off next week but would prefer not to changing the head gasket but will if this would help, anyway I can check as I can get hold of a compression tester to test the head, does anyone know what readings I should be looking for?

Any other ideas of what could be wrong will be greatfully recieved.

Many Thanks

Adam

Kitch · Post by **Kitch** » Fri Aug 25, 2006 7:05 pm

Sounds more like air is getting in somewhere, if it was the head gasket it would probably fizz over when you rev it, rather than just idling.

Adam · Post by **Adam** » Sat Aug 26, 2006 12:46 am

Cheers Kitch, I was thinking about it tonight and was gonna change all the hoses and clip before the head gasket, i've got some time this week so i'll be getting it sorted whatever needs doing.

Thanks again.

ianselva · Post by **ianselva** » Sun Aug 27, 2006 2:06 am

These are exactly the same symptoms as my TZD . They only occurred after I changed the head ,having had the cam belt strip. As I have used mostly the same hoses clips etc I am thinking it must be a crack in the head and am about to fit another if it stops raining long enough.

Ian

Adam · Post by **Adam** » Sun Aug 27, 2006 2:09 am

Cheers Ian, I'm going to strip the head on monday and if there are no obvious gasket problems will be changing the head.

Adam

tom · Post by **tom** » Sun Aug 27, 2006 12:39 pm

Take the expensive guesswork route if you want to guys but the correct way to avoid wasting a lot of time and money is to take the car to a garage and ask to watch them do a compression test. Unnecessarily pulling the head of an XU is a very very stupid thing to do!

ianselva · Post by **ianselva** » Sun Aug 27, 2006 12:43 pm

How is a compression test going to tel whether the head gasket's leaking , the valve(s) leaking or the head has a crack ?

ken newbold · Post by **ken newbold** » Sun Aug 27, 2006 12:50 pm

ianselva wrote:How is a compression test going to tel whether the head gasket's leaking , the valve(s) leaking or the head has a crack ?

It wont, but you will know for sure if the head needs to come off. Any of the above faults will require the head off to cure, but the fault may lie elsewhere not within the engine.

tom · Post by **tom** » Sun Aug 27, 2006 12:52 pm

It will tell you whether it is NOT any of those things. A leaking valve will have nothing to do with your water loss. A failed compression test will need to be investigated anyway but a pass is another matter.
You have used the same hoses and clips. You may be drawing in air, or you may have a bleeding issue.

BX Bandit · Post by **BX Bandit** » Thu Aug 31, 2006 9:16 am

I had a similar problem and went through a ball ache experience. I had lumpy start-up/idling when cold, bubbles in header tank and coolant in oil.
I replaced head gasket outside in January in Holland (ouch!).

Problem immediately returned

Had head pressure tested, leak was between water jacket and inlet port. As the port is not under compression I was confused as to why bubbles were coming through to the header tank

I invested in a new head and fitted it. Same problem

I took to local Cit dealer who pointed out radiator was cold - it was blocked. 2 Radiators later (1st one was broken on delivery), no joy. Although this sounds unlikely, I assumed it was the block

, either that or the new head was porous too.
Eventually, I got a recon engine which is still going fine. It was a frustrating and expensive experience.
Clearly, I hope you don't go through this but the above may prove helpful in some way

jeremy · Post by **jeremy** » Thu Aug 31, 2006 9:35 am

1.7TD's used to be prone to head cracking - I say used - as they don't seem to crop up on boards these days.

In fact many had small cracks and it was common for them to seal up as soon as the engine started to get warm - so no symptoms when hot.

If you apply positive pressure and the pressure is held while the engine has stopped I think you can safely eliminate air being drawn in. If it leaks from somewhere - you've found your problem. Postive pressure could be simply observing your engine when its switched off - if it pressurises when running. Otherwise a pump could be used with a suitable adaptor - or one of those rad cap pumps garages use.

Brian · Post by **Brian** » Thu Aug 31, 2006 10:21 am

Hi Adam,

This is a test that I carried out, but you will require a compressor or foot pump and a modified heater glow plug to get the air into the cylinders.

1. Bleed the system to remove air, fill to rim of header tank with water, leave cap off.
2. Cam cover off, all glow plugs removed.
3. Screw in modified glow plug to the cylinder to be tested.
4. Set this cylinder to TDC on firing stroke both valves closed.
5. Apply air pressure.
6. Observe the water level in the header tank and air bubbles.
7. Repeat on other cylinders.

This test will indicate for any blow back into the cooling system, and the location.

Good luck

tom · Post by **tom** » Thu Aug 31, 2006 6:06 pm

But the actual cylinder pressure when the fuel burns is immense, so that won't necessarily tell you anything. at 24 to 1 CR, you are at around 360PSI so it does need to be done properly. The standard test, (Make it a sticky please, Jon) is to run the engine from cold for a minute and stop it again. Now remove the filler cap and if water emerges, the HG is Shot.

ianselva · Post by **ianselva** » Thu Aug 31, 2006 6:26 pm

Agree with you about the air pressure test , especially as I have been battling against overheating on my historic racing car all season and all the air pressure testing both with the head on the engine and on the test rig show no problems because you can't supply the same pressure as combustion chamber pressure.
However I currently have a different slant on this problem on my TZD . If I do the test as described ,the header tank is fairly quickly under pressure and some bubbles can be seen in the water however I have since done 200 miles both fast and slow and the water level doesn't drop and the warning light never comes on.????????????
I am going to Goodwood for 3 days which will involve long fast bits and I expect a fair bit of traffic creping . So we'll see what happens.

Ian

jeremy · Post by **jeremy** » Thu Aug 31, 2006 8:50 pm

Longshot - bottom hose - collapses when very hot and water pump working hard - engine overheats, boils and chucks out water?

BX Club Forum

Head Gasket or New Rad???

Head Gasket or New Rad???

\