Overheating/Bleeding coolant system

[Coradia63]

Hi all,

I have a 1995 2.5TD Ford Freda which I bought with a know overheating problem as a little project to do in my spare time since I have had it I have stripped the cooling system down found it was clogged up with 'Jelly' I'm guessing the previous owner either mixed coolant types or used to strong a mix anyway I have flushed the system several times removed the radiator and cleaned out I have also replaced most of the coolant hoses will get round to them all as I go system now seems to be clear I also found the thermostat had been drilled so I have replaced it the previous owner had a new water pump fitted.

I don't yet know if the head is cracked I want to prove it before I strip the head off (I may be lucky!) the problem I am have is bleeding I have followed the you tube videos all goes well the stat is opening just over 80degs the bottom rad hose gets hot but after 45mins there is still lots of bubbles coming out in the funnel but only when you rev the engine there is no bubbles at all if you dont rev the engine I have done this for up to an hour with no change so I tried refitting the radiator cap and removing the funnel and left engine running system did become excessively pressurised and the engine seemed to peak at 88-90degs and would not get any hotter at the moment I cant take it for a test drive as its not insured should I expect it to overheat idling on the drive if the head is cracked or will I only know if I take it for a drive and any suggestions on the bubbles?

Thanks

[Simon Jones]

Hi and welcome to the forum. Lots of bubbles after bleeding and excessive pressure in the coolant system are the typical symptoms of head gasket failure or a cracked head. Where it gets a bit more tricky is that when you run the system with the expansion tank cap off, the boiling temperature of the water will be lower than when under pressure, so bubbles in the water may simply be it turning to steam.

You mention it had a known overheating issue when you got it. Do you know what steps the previous owner took to diagnose and fix it (other than new water pump and thermostat mod)? Removing the stat will often mask an underlying issue with poor circulation or excessive temperature. My view would be that it has been driven while overheating to the point where the needle went into the red, then the head will be cooked by now, even if the original fault was perhaps water pump, gasket or stuck thermostat. If it were me, I would take the head off and get it pressure tested, but then budget for replacement anyway. There is always a very slim possiblity the there is a crack in the main engine block around the water jacket, but this appears to be extremely uncommon. Good luck with your project: it sounds very fixable if you have the time, enthusiasm and funds to get see it through

[Coradia63]

Hi Simon

Just noticed the typo I meant to say the system doesnt become excessively pressurised with the radiator cap back on the previous owner didnt seem to think it overheated to much..... his local garage changed the water pump but didnt cure it when I stripped the coolant system down I found the radiator was blocked almost solid internally with the 'jelly' type substance Ive checked the radiator fans and engine fan all are working ok just seems to get lots of bubbles when reving the engine whilst bleeding. I think the easiest way will be to get it temporaily insured and take it for a test drive.

[teenmal]

Hi Coradia63,

It might be worthwhile bypassing (Loop) the front heater matrix just in case it is blocked.

Cheers.

[Northern Bongolow]

get a 2 bar pressure gauge and fit it into the end of the bleed pipe using an adapter. seal the system -- put the caps on and run it on the drive.
the normal for the system is about half a bar when up to temp and in normal driving.
if you get no or low pressure its got a leak, or the cap/s are leaking.
if you get too much pressure -----getting up to three quarters of a bar or higher then it points towards head cracked, combustion gasses escaping into coolant is the norm.

the only problem with this way of checking is when you have a tiny leak and its pressurising it may show as normal.

pressure is the only way to check the system as its constant throughout the entire system, or very nearly, where measuring temps are very localised.
ive fitted an in car 2 bar pressure gauge for everyday running, and just ignore the temp gauge.

are you sure its air bubbles you are seeing or is it just waterpump turbulance

good luck.

[321Away]

there are no rules with bleeding bongo's, some take 20 mins, some takes hours so dont lose heart if it doesnt bleed out instantly. Hold the car at 2500-3000rpm as opposed to driving it, the bubbles do stop when you rev it as the pump is drawing the water in, and you do usually get some bubbles on backing off. When you start the car from cold, is it smooth or jumpy? failed head/gasket usuall mean white smoke and rough idle for short time. Ive seen some bongo's that just dont seem to want to bleed and the only way to do them is to let them pressure up and push some water out and refill as the level drops

Julian

[Coradia63]

Hi all,

Thanks for the info I've got a few more checks I can do this week.

Julian,
The engine starts from cold first time and idles very smooth there isnt any white smoke in the exhaust its very clear.

I've managed to sort out temp insurance for the weekend so I will find out one way or the other!

Cheers

[crazy uncle gray g]

Hi all,

I have a 1995 2.5TD Ford Freda which I bought with a know overheating problem as a little project to do in my spare time since I have had it I have stripped the cooling system down found it was clogged up with 'Jelly' I'm guessing the previous owner either mixed coolant types or used to strong a mix anyway I have flushed the system several times removed the radiator and cleaned out I have also replaced most of the coolant hoses will get round to them all as I go system now seems to be clear I also found the thermostat had been drilled so I have replaced it the previous owner had a new water pump fitted.

I don't yet know if the head is cracked I want to prove it before I strip the head off (I may be lucky!) the problem I am have is bleeding I have followed the you tube videos all goes well the stat is opening just over 80degs the bottom rad hose gets hot but after 45mins there is still lots of bubbles coming out in the funnel but only when you rev the engine there is no bubbles at all if you dont rev the engine I have done this for up to an hour with no change so I tried refitting the radiator cap and removing the funnel and left engine running system did become excessively pressurised and the engine seemed to peak at 88-90degs and would not get any hotter at the moment I cant take it for a test drive as its not insured should I expect it to overheat idling on the drive if the head is cracked or will I only know if I take it for a drive and any suggestions on the bubbles?

Thanks

I take it you mean refitted the expansion tank cap? surely your not doing the bleeding procedure with the radiator cap off??

[Coradia63]

Yes I meant the expansion tank !

[Coradia63]

latest update finally got insurance sorted out and took for a test run today did about 35 miles and it didnt overheat I have got a digital temp gauge fitted with the sensor connected to the back of the cylinder head the temperature ranged from 88deg on the flat/downhills and got up to 96deg going up along step hill with my foot down hopefully I bought bargain after all