your thoughts on 365 cooling issue please

As mentioned in another thread, last week I bought a 365 GT4 2+2 which i drove home on Friday. It ran perfectly for 130 miles on the motorway with the temp needle straight up until I hit rush hour traffic then started to get hot. So hot in fact that I had to keep stopping for it to cool down so I could get it the last 20 miles home. I added around 2litres of water topping it up during this period.

I have zero time to check the car over before I go on holiday on Tuesday but showed a few friends the car yesterday and noticed the sides of the the top hose were drawn in (it wasn't like it when I picked the car up). I also found that the rubber seal inside the low pressure rad cap (fitted to the main filler neck) was being drawn away from the cap down into the filler neck. Obviously some form of suction is going on inside the rad for these symptoms to occur.

I ran the car with the main rad cap off and the water level went up and fell as what appeared to be air was expelled, I also noticed that the top hose was expanding and contracting (pulsing) as I gently revved the engine. As the temp rose to the normal position the hose started to return to its normal shape and the car didn't seem to get hotter than 195 (straight up on the gauge) but water then started to overflow from the still capless filler neck (I assume from expansion seeing that the cap was still off) so I refitted the cap but didn't run it for too much longer. Once pressurised the top hose looked normal.

The car runs and drives perfectly, there's no water contamination in the oil or signs of oil in the water - that said the water in the rad had a mauve tinge to it, probably indicating that some leak kind of leak additive had been poured in at some point. There are brown water stains on the header tank (maybe from a failed pressure cap at some point ?) but it seems to be holding pressure and I'm fairly sure that when it was getting hot in traffic water was coming from the header tank overflow outlet.

My questions are:

1.Is the cooling fluid flow top entry/ bottom exit ?
2. I understand that this is a circuit so in reality both occur but is the pump biased to pull or push fluid through the rad ?
3.If the thermostat was stuck shut would the water pump cause this suction effect ? A stuck thermostat seems unlikely due to the 130 mile drive home on a warm day at 70-120mph with no real temp problem.


I suspect that at the very least the rad may be partially blocked - all thoughts and suggestions gratefully accepted.
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Note newly rebuilt alternator in the photo - this expired on the initial drive home on Wednesday resulting in an aborted trip, then a drive from Birmingham to London in my sons car to get the alternator rebuilt followed by a trip back to refit it on Friday before attempting to drive my new purchase home again.

Goodbye alternator problem, hello cooling issue............

 

I'm pretty sure that the pressure cap on the expansion tank may be the problem here UNLESS they're supposed to be rusted to pieces and fall apart when removed !!

Thanks Howard for your advice in pointing out the one thing I could easily check and kind offer to check the tank over for me while I'm sunning my gorgeous, lithe body on the beach in Marbella.
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You think I should try to clean it up and refit it ?

I've removed the expansion tank which was full of water due to the broken piece from the cap sealing it shut. I pulled the busted bit out with a pair of pliers and drained the old entombed brown rusty water out. The tank itself seems ok (see pix) - not too rusty and doesn't seem to be perforated but time will tell when it comes back from trusty old Howard,

The main rad seems fine but will need flushing, new caps and hoses etc.

Hopefully the problem will be solved - who knows ????
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I'll buy my bits from Superformance as they're very near where I live.

Superformance ferrari dino ferrari v6 ferrari v12 specialists 308 246 206 fiat dino 355 328

 

They were fitted correctly, only the pressure cap on the expansion tank is crusty and has fallen apart.

The non pressurised cap on the main rad is fine although the rubber seal has seem better days and will be replaced.

I think that the expansion tank issue is indicative of a car which has been in long term ownership but has had minimal use with few long journeys. I know it's been checked over and had the oil changed regularly and been taken for the odd 10 mile drive but not used in real life traffic so never really got hot.

I'll check the car over fully and change all the fluids, hoses etc before using properly.

 

Howard has hot tanked the expansion tank and it's toast - would leak like a sieve apparently !

Superformance don't stock a 365 tank so I've ordered a 400/400i tank and new caps which is the same but with a different mounting bracket. Howard will swap the bracket over from the 365 so when I get back from sunning myself in Spain I'll be able to refit and see if the overheating issues resolved. How's that for a good friend

Total parts cost is around £280 delivered and is a genuine F part. By the way, I get 10% disc from Superformance on most parts if it helps anyone.

Will keep you all posted

 

You're prob right about the rad but it seems logical to start with the obvious and work backwards. Theres a chance that the rad may be ok because there were no leaks from it on the 150 mile drive home but i agree it could be partially blocked. I'll drain the system, flush everything through and check the thermostat and flow before installing the new tank and doing any more mileage.

Everything else looks fine externally and there's no sign of corrosion in the main rad. The expansion tank is (stupidly) made of steel so prone to corrosion in the way that the Ali components aren't - there's a chance that the rest of the system could be ok if I'm lucky but considering how my lucks been the past 12 months probably not !

 

Well the last one lasted 39 years without being used much for the past 28 of those so I guess you're right. Like all my other cars I'll use this one - no point being pretty and not going out is there ?

Will consider using tank sealant before installing expansion tank - anyone got any comments if this is a good or idea long term ?

 

Duly noted Ken. The fans cut in fine when the car is idling when hot but that's also when the overheating problem occurs.

The fans will be checked over for operation but other than that they cut in and that the operating speed is ok there doesn't seem to be much else to check.

This car is very original, probably due to spending 27 years with the previous owner but I've noticed that Superformance do a replacement fan/motor unit which has a 4-bladed fan instead of the 3-bladed unit which is fitted as standard to the car.

Superformance ferrari dino ferrari v6 ferrari v12 specialists 308 246 206 fiat dino 355 328

Has anyone fitted these and was there any cooling improvement ?

 

The odds are that they're ok but it's an interesting thought, prob wouldn't have even considered checking that so thanks for planting the seed.