My 944 saga

[Mikey44]

Hi all,
I’ll try to keep this short but in all fairness I’m staring into the abyss and this thread could go on!

First off the run down of my 944 and what I know. It’s an ’84 NA 944 2.5 LUX.
She’s currently at around 75k on the clock and since purchase the temperature has been a bit a little erratic. The story goes that the car was laid up for around 8 years before a guy who I bought I from, purchased it and spent over £1000 on it, getting running right. Full belts (incl water pump), fluids, terra-cleaned, brakes, fuel lines, quite a lot happened. He ran out of time and patience I guess.

I ran her up to north Wales once and I think that finished it off. It may have been a combination of things but the result was over pressurisation of the coolant system, distinct smell of fuel and poor power at times. I did change the thermostat for a genuine one and drained and flushed coolant and that did seem to help a bit. But there were more signs the head was on the way out, so after much scrimping last year, I bite the bullet and have just had the work carried out.
With the work done, she runs well but unfortunately, still warm. Not over heating apparently but close enough for the fan to want to fire up too often, even at this time of year.

The details to add here are the fact that I had to buy a new head from the garage because mine had been previously repaired and had badly corroded. The mechanic noted that in some of the galleries of the engine, corrosion could be seen, so obviously this has to be considered in the bigger picture.
Broke and obviously a little disheartened, I have to plough on. Word from the garage was that it’s a resistance in the cooling system causing this overheating. I need to rectify this situation ASAP if I don’t want to see the head fail again.

I’m putting this thread up because I’d like to hear some experiences and just general thoughts on the matter to keep me sane. The history of the car isn’t extensive but all round she has good body work and has not been modified.
The advice has been to start the process of elimination again, perhaps starting with the oil cooler and the rad. I’d like to just through more money at it but it’s already looking like a soup and noodles month. [s2]

 

[PSH]

Hi Mike

I'm not that clued up on N/A models but two things come to mind, are you sure that the coolant is bled properly? 944's can be a pain to bleed. The other thing should have been addressed with the new head but if the car overheated badly it would probably have required the head to be skimmed, now you say that a replacement head was found, was this checked for flatness, in fact, was the block too? The head at least should really have been skimmed anyway being an 'unknown' component. might be worth changing the header tank cap as these can cause problems. As I said I'm more familiar with the turbo which has two fans with two settings, one runs to keep the car temp where it should be, if the temp gets higher the second fan kicks in and brings the temp down quickly, does the N/A have a fan switch with two speeds?..i don't know but others should be along soon with more experience of the N/A model.

Hope you get it sorted soon, a well running 944 is a joy to drive..

Pete

 

[Mikey44]

Hi Pete and thanks for the reply. The head that was the replacement was checked thoroughly and pressure tested before fitting.
The header bottle was replaced for a better one and the cap is new. The cooling system was filled and bled using the right kit.

 

[Mikey44]

Hi Mikey,
First thought is the radiator - the corrosion debris will have ended up somewhere. Has it been removed and backflushed? I'd suggest looking for a local rad specialist to check it out. Re-coring might be an option if it can't be cleared.

 

[Mikey44]

Hi Steve,
I think the plan for the rad is to rig up another one on the car to rule it out. I will report back when this is done.

 

[GlennS]

Not over heating apparently but close enough for the fan to want to fire up too often, even at this time of year.

Define "too often". 944s run their fans frequently and often, far more frequently and noticeably than a modern car does. "Even at this time of year". A garage unfamiliar with the breed might identify this as a fault where none exists.

 

[vitesse]

Could be a sensitive fan switch.

 

[robwright]

They do run hot TBH. How does the dash gauge compare to when the fans cut in? What sector is it reading in? Could even have the wrong thermostatic switch on the rad.

 

[Waylander]

Buy a cheap infrared temp gun off the bay and scan the rad, I would take a bet it’s a bit chocked up

 

[Mikey44]

Define "too often". 944s run their fans frequently and often, far more frequently and noticeably than a modern car does. "Even at this time of year". A garage unfamiliar with the breed might identify this as a fault where none exists.

They are a Porsche specialist and a number of 44's pass through there. This runs up to half way on the guage, creeps past and the fan comes on, it drops a little but it's creeping up all the time. I don't think this is under load either. I've read other peoples accounts of coolant changes etc and this isn't normal.

The garage have had an infrared gun over the engine, including the rad, it doesn't appear to be an issue. They also rigged up a doner rad and it performed the same.

There does seem to be a lot of confusion about thermostats. I purchased the stat in there from Max at Fraser part and he paired me up with a stat from my registration. The technician said he may remove the stat to see how the system performs.

 

[GlennS]

This runs up to half way on the guage, creeps past and the fan comes on, it drops a little but it's creeping up all the time. I don't think this is under load either. I've read other peoples accounts of coolant changes etc and this isn't normal.

"Ideal" temperature for a 944 should be the middle of the gauge. Most of them, however, read lower because the gauges are a bit tired. Under normal operation, with a perfect gauge, I would expect the temperature to fluctuate between the middle of the gauge and 3/4 with the fan cutting in at 3/4 and dropping it to just below the middle (rinse and repeat). You need to be driving at a reasonable, constant speed to get enough airflow to cool a '44 without the fans kicking in. There's not much in the way of natural venting into the engine bay. They will routinely use the fan(s) in stop/start town driving or idling.

 

[vitesse]

Our grey 924S used daily -many local short trips by my wife-generally accorded with the comments made above -fan cut in climbing to 3/4 gauge reading & invariably on hot days in slow,queuing traffic-& if so,would carry on running when stationary until temperature dropped enough.Effect of the fan has always been a quick response in temperature drop.
Later last year ,my wife started to notice the fan cutting in more frequently,gauge rising to red nearly until eventually on one journey ,she thought it wise to pull off the road ,out of the traffic & let it cool down-fortunately only a mile or so from home.She rang me & I advised her to let it cool down for about 15 mins then drive home the back road fairly slowly-fan was running full tilt when she arrived .

My suspicions centred on the thermostat (we've had her car since 1991 with no cooling problems apart from the heater transfer pipe getting corrosion pinholes).
As I already had a Porsche OE replacement(for my red trackday car really),I fitted that finding that the original was jammed closed because the wax bulb housing had failed.I suppose not bad for 32 years service!

Compare that with the red 924S-it has always run cool since I bought it 9 yrs ago but if queued for 5 mins or so rapidly had a rising gauge needle heading for the red sector.1st time it happened,i was really panicking ready for a burst engine,hand on ignition key but the fan cut in & temperature rapidly dropped.Was always a sensitive moment when this occurred so changed the stat,which looked OK & since then,engine has run at the recommended temperature just high of centre,with fan cutting in at 3/4's.Normally the ram effect on trunk roads/motorways seems adequate & I only see the fan cutting in in slow traffic.

I now Max well & am sure the stat he supplied will be correct but you could have a rogue one which the strip out may show-easy to drop it in a pan of hot water with a thermometer to check it.

 

[jasonp]

Blimey!
I was very peeved when i noticed 2 or 3 tiny bubbles on my bonnet!,,,,,
really feel for you Mikey,,,,,,
all the very best and once sorted you will have a great car hopefully,,,,jasonp

 

[Mikey44]

My suspicions centred on the thermostat (we've had her car since 1991 with no cooling problems apart from the heater transfer pipe getting corrosion pinholes).
As I already had a Porsche OE replacement(for my red trackday car really),I fitted that finding that the original was jammed closed because the wax bulb housing had failed.I suppose not bad for 32 years service!

Thanks for all the input...everything helps me understand the common stuff to the random things a 44 can throw up.
Based on what people say to me it seems like the 944, i ftrreated well, is an exceptional classic and pretty reliable. Sadly, if neglected, they can suffer a bit.
Thermostat being checked today or tomorrow, a WYNNS coolant flush to. Fingers crossed it’s something simple !

 

[Mikey44]

Hi all,
I wanted to post an update here, not just for me but again to strike up discussion to those who know more than I.

I should be picking up the car today, and I’m obviously dreading the bill. I haven’t seen the car since end of February.
Head gasket etc all complete, they have sorted the issue of the expansion tank overflowing after a run and she appears to be running (on temp gauge) at 12-1 o-clock.
The boss there thinks that the car should run at a lower temp, a Porsche specialist he spoke to recently thinks it’s fine.
So for now, I’m taking the car away and seeing how she runs.

Something’s I need to consider;-
The thermostat has had a small hole drilled into it, this improved flow of the cooling system.
A different radiator was tested (not the exact one for my 944) which appeared to improve the temperature. When swapped back to mine, it appears to run hot again.
It has been suggested, even though my radiator looks like a fairly modern replacement, to replace or re-core my current one.
Although during strip down the water pump looked to be in good condition, it’s unknown what kind of replacement it had.

If the car runs consistently at 12-1 o-clock, will this eventually cause the same issues the car has had before? I.e head gasket failure.

 

[Sy924]

Have you flushed the radiator through with clean water from a hose with decent pressure? Water should rush through with no real resistance. If it seems to take a long time to come through or water backs up quickly then signs probably point to a new rad.

Additionally, if you're worried about the head, a compression test might tell you something. A compression gauge doesn't cost much and if you can change spark plugs you can do a test.