# Engine overheating 1991 Fiat Ducato



## WittyWanda

Hi All

I did post a little while ago with the same problem, but don't seem to be getting anywhere so sorry for the repeat.

My mother has a Fiat Ducato 1.9TD 1991 Mayfair. She is having problems with the engine overheating. She has had a new thermostat recently, but it still continues to happen.

The symptoms are; the radiator water disappears every journey though there appears to be no leaks, the overheating does not happen every journey though does most of them!

The fan does kick in when the temperature rises to approx 100 (the van appears to run at 90 when ok).

The van has a new cylinder head and passed a recent block test.

One of the hoses gets very hot during the overheating.

Garage appears completely flumoxed!

Would be grateful for any help as she has spent a lot of money on the engine since she purchased it.

Thank you

Jay )


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## Wizzo

It's not unusual for the temperature to go over 100deg. Mine does when labouring uphill in anything less than 4th gear and believe me it labours up every hill it comes to!

However it soon drops to its normal temperature of around 85 once its back on the flat. Even so it does not lose water.

It might be worth having the radiator cleaned out or even re-cored. There is a national company that supply refurbished radiators. They are called Serck Marston, or Serck Intertruck or in some cases just Serck. They may keep one for yours in stock but if not they can put a new core in.

JohnW


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## Wizzo

Another thought has just occured to me. You mention that the temperature reaches 100deg. If it is not going higher than this then it may be an indication that the radiator cap is not doing its job. The radiator cap keeps the cooling system under pressure which means that the water will not boil when the temperature reaches 100deg. It keeps the system liquid at temperatures well over the normal boiling point.

It would be worth trying a new one first before looking at the radiator.

JohnW


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## emmbeedee

I am not familiar with your particular engine however my experience with thermostats is extensive if pretty old (so is the MH) so here goes:
In general, thermostats are often blamed for overheating, but in reality rarely fail & on those occasions they normally stick open, which leads to not reaching the correct temperature rather than overheating.
Problems can arise if the thermostat is sticking in its housing, due to corrosion. This can sometimes hold the 'stat shut when it tries to open. As you say you have a new head this is unlikely.
*WARNING* take care not to scald yourself with steam if trying the following test: 
Thermostats can easily be checked by suspending them in a saucepan of water, using a piece of cotton trapped in the valve. Place the saucepan on a hob & bring to the boil. When the valve starts to open the 'stat will fall to the bottom of the pan. The opening temperature is normally stamped on the 'stat & can be checked using this method if you have a suitable thermometer, but even without you will see the 'stat open fully if it is working correctly.

The most common cause of overheating, & generally overlooked, is the radiator filler cap, which usually doubles as a pressure relief valve. If the filler cap does not have a pressure relief valve there will be one somewhere in the system. If this valve is sticking it will invariably lead to overheating. Radiator caps often have a rubber seal which can expand with age, causing it to stick & fail to open. This would be the first thing to check IMHO. If in any doubt replace the cap.
Other things to check, the radiator as mentioned above (I would try back flushing before replacing, surprising what comes out) & also the water pump. The latter, if the original, may have corroded.
Hope this helps, if I think of anything else I'll post again but going back 30 years here so stirring up the grey matter!


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## emmbeedee

Well, Wizzo beat me to it re the cap!
(Slow typing!)


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## trekki

*overheating*

Hi when they did the block test did they pressurise the whole cooling system as that should have shown any leaks apart from that I must agree with what has already been said
Good luck


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## merctoby

*some things to look at !*

hello and hope i can help you out ,

you say you have had a new cylinder head gasket fitted , well i agree with the majority here , and would go a few more as well !/

take a look at the water pump . under neath their is a small drilling about say 6mm , this is for a seal incorperated in the water pump some time,s the seal goes and it will leak , this is quite common ,second as the head gasket was done check out the timing is spot on if advanced this will cause overheating . and cause that seal to leak also , have a water jacket test done 1. then have a compression test 2 , as water can be pulled in to the cylinder whilst stroking and expelled out causing pressure to the water jacket , . a check to check!! where you would add oil to your engine ! take the cap off and look inside the cover you should have oil residue so look to see if it looks like cream , if it looks like cream you have a problem water getting into your cylinder block this would explain where the water is going to none to outside but inside your engine . the thermostat do as suggested put it it in boiling water saucepan chech as you see it in pan the thermstat open . if it does good but you could have an electric fan that switch,s on at temp level if this temp control switch is defective this will cause you to overheat also . so this would be my list , 
but then i am old school fitter /mech.

but any way good luck and i hope it turns out to be the lesser of the 2 evils ? cost!!

bye for now then , denton. 8)


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## sideways

If the water disapears with out an external leak its either going through the engine or boiling away, as already stated water boils at a higher temparature when under pressure so try a new cap, second if the water pump or the impellor has failed in any way the water will boil away as its not circulating the cooling system.


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## erneboy

I would fit a new water pump, it won't do any harm as they have a limited life any way, and remove the thermostat for a while and see if the problems continue.

I do also think a gummed up radiator may be the problem, Alan.


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## ttcharlie

I had a similar problem with a TD engine in a VW T25 which kep on loosing water

Its passed all it pressure tests/sniff tests etc etc but still kep on loosing water.

We tried the cap and flushing the system and all was good.

It turned out to be the 7 cracks in the cylinder head! tests are only so good....


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## WittyWanda

Hi all. 

Thank you do much for all your replies. Mum has had the radiator cap changed as well as the thermostat and this did not help. 

Today she had found an oil leak in a 'hole' which appears like it should be there (best description I have!) at the bottom of the engine beneath where the cylinder head sits. We believe this should not be there!

I'm not sure if the whole cooling system was pressurised when the block test was done I will get her to check that. 

Wizzo. Thank you for your input regarding the temperatures. Reaching 100 degrees may not be an issue, unfortunately the temp foes not plateau but continues until the van overheats at around 130. 

I have passed on all your comments to my mum who is also grateful for your advice. I am hoping that we can find a trustworthy & cheap (which don't always go hand in hand) mechanic who
Can get to bottom of the problem and fix it. 

With much appreciation 

Jay xx


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## Mrplodd

Are you sure its an OIL leak?? 

From your description it sounds very much like the hole that has already been mentioned in the water pump!!

If there's coolant (water coming out of there its the water pump thats ******* and needs replacement (even if thats not the cause its still knackered!!)


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## Wizzo

WittyWanda said:


> ... but continues until the van overheats at around 130.
> Jay xx


It's beginning to seem as though the knackered water pump theory is right.

The water pump will be somewhere near the bottom of the engine and is driven by the cam belt which runs in a cover on one side of the engine (most likely the left hand side as you look at the engine from the front). If your hole is on that side then it could well be the water pump drain hole.

I know it is extra expense but if you are going to change the water pump it may be worth doing the cam belt and pulleys as well, the cam belt has to be removed to get at the water pump.

JohnW


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## davidmac

I would think that the radiator is not an aluminium one and would suggest you check that the fins are still fixed.If you can move them about they are not in proper contact with the cores and will not conduct the heat sufficiently well enough to cool the engine properly.
Regards David


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## merctoby

*hello again can you !!*

it might help really if you could post some picture,s of your concerns , 
it might help enormously with the guys helping out here , 
and interesting with better theory s,

but the pictures , are the norm , usually if the water pump is or has been leaking where you see the weep hole the drilling at the water pump it gives you a helpful sign like a dribbling stain rusty colour this means the seal is damaged . where the head meets the block again leakage and how bad it would appear , so a picture of all the items that concern you .will help a bit for me ,

do the water jacket test again pressurise the system and leave at least 4 minute,s this will prove very helpful with the answer ,and a compression test of each cylinder will either indicate this good or bad . 
but tell me this please or maybe i have missed some thing what is the mileage ?.

in the end i hope it is the water pump as this will be the cheapest option for your mother , hope all ends well .

good luck . and best of luck!.

denton.


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