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Eric de Back (Eric328)
Posted on Wednesday, June 13, 2001 - 8:58 pm:   

Well, now my overheating problem on my 1989 328GTS is finally fixed. The car isn't overheating anymore. All it was in the end, was the water pump which was leaking when the coolant system was under pressure. It never leaked when in the garage (that's why I never thought anything was wrong there) but only when I was on the move. That caused coolant to simply disappear from the system and eventually led to overheating problems.

/rant on

So far, I've paid for replacement thermostats and thermoswitches and god-knows how many liters of coolant and man-hours when the problem was mis-diagnosed right from the start. It really bugs me that some workhops see replacing parts (at customer's expense) as an expedient way to "fix" problems. Especially since parts prices are ridiculously high.

/rant off

Oh well: at least I'm happy that things are right again and that I've found a (new) mechanic who thinks about what is right for me instead of his wallet.

'75 308 GT4 (Peter)
Posted on Friday, May 18, 2001 - 9:26 pm:   

Verell: I f---ed up that ring when trying to remove that inner bearing. From what I remember, the outer diameter rests on the internal clip, the internal diameter rests on the bearing. Which is pretty much what you figured out.
Verell Boaen (Verell)
Posted on Saturday, May 05, 2001 - 9:27 pm:   

I'm in the middle of rebuilding my '82 Euro 308 QV's water pump.

In the water pump picture posted previously in this thread, the large, narrow washer between the circlip & the rear bearing is angled to act as a spring, presumably to tightly retain the bearing.

My old washer was so badly rusted that I couldn't tell which way it was facing. Which way does the inner edge of the washer go?

My guess is that the inner edge presses against the rear bearing's outer race, and the outer edge presses against the circlip. Otherwise, the inner edge looks like it may extend inside the circlip as it's width narrows.
Verell Boaen (Verell)
Posted on Saturday, May 05, 2001 - 9:24 pm:   


When I got my '82 Euro 308 QV's water pump apart, the seal ring design was the one in the picture earlier in this thread, not the newer smaller diameter seal ring one that came in the 'QV water pump rebuild kit from T. Rutlands. The 2 seal designs are:

In the older design (shown in the picture below), the two parts of the seal are roughly the same diameter. The ceramic ring fits into a rubber seal that holds it & fits in the water pump housing. The mating ring slides over and seals onto the pump shaft. The rubber holder for the ceramic ring is about the same size as the water pump bearings.

This seal is shown in the '78 308 GTS/GTB parts manual, & in the '93 Mondial QV service manual.

In this design, the ceramic ring & the seal that holds it is about 2/3 the diameter of the bearings. The seal holding the ring fits into a recess in the back of the impeller. The mating part slips over the pump shaft, & and I think it's a press fit into the water pump housing.

(I think it seals against the housing with an O-ring. (At least the kit has an O-ring that I couldn't figure out where else it could go.)_

The '89 308/328 Service Manual shows this seal, as does the '84 308 QV Parts Manual.

Other than not having the right seal, the water pump readily came apart, & looks like it'll go together just as easily.

1) Front bearing: After removing the pump shaft, slide the spacer tube to one side. You can then slide a long socket or a fat punch thru the center of the rear bearing & use the spacer to drive the front bearing out by it's center race.

2) Rear bearing: My housing had some substantial caked on deposits in the are between the bearings.
Probably because both weep holes were plugged up!
YOU MUST REMOVE THESE DEPOSITS with a small round wire brush in a drill. If you try to drive the inner bearng out with heavy deposits, you'll at minimum badly jam the bearing, and either break the center race out, OR CRACK THE PUMP HOUSING!!!.

Chris at T. Rutlands tried to discourage me from rebuilding my pump saying that most housings were found to be cracked & hence unusable. IMHO, the only reason for the housing to crack is nod doing tip #2!.
Eric de Back (Eric328)
Posted on Tuesday, April 10, 2001 - 1:55 am:   

OK I lied: I didn't install it myself I had the dealer do it: All I know is that is was OEM (made in Germany - rolls eyes) and that the printed 'opening temperature' was 82deg. Celcius. Looked very similar to the one Peter posted a picture of.

'75 308 GT4 (Peter)
Posted on Thursday, April 05, 2001 - 4:00 pm:   

Here are pictures of the cooling system distribution manifolds, the thermostat and the waterpump. The markings on my thermostat read: "MotoRad 5, 71°C/160°F". Seems quite low activation temp, eh?

'75 308 GT4 (Peter)
Posted on Thursday, April 05, 2001 - 3:23 am:   

I'd be curious to see those numbers too. I've got the entire cooling plumbing removed from my engine and my water pump apart. I noticed that thermostat is not typical-looking of a standard one. Although all the writing on it is in english, so I'd doubt the one in my car is a Ferrari item. Will post pictures of it soon.

Check those studs holding the neck down, I snapped a stud. SEVERE corrosion.

A note of caution: the water pump is a design where its: easy to put together, but a b---- to take apart!
Erik Jonsson (Gamester)
Posted on Thursday, April 05, 2001 - 1:28 am:   

Which thermostat # did you use... A Stant? or genuine Ferrari?
Rob Lay (Rob328gts)
Posted on Wednesday, April 04, 2001 - 10:49 pm:   

That's good, my similar problem had turned out to be the thermostatic sensor on the radiator fans.

Until I made it in to the shop, I bypassed the sensor so the fans were always on.

BTW, when I first overheated, it only took about 1 minute of driving around at 30 mph to get the temp back down.
Eric de Back (Eric328)
Posted on Wednesday, April 04, 2001 - 10:23 pm:   

I replaced the thermo switch on the radiator which didn't really help and then the thermostat itself. It must've been faulty because that did help. She's running like she should again.
Thanks guys.

Eric de Back (Eric328)
Posted on Saturday, March 03, 2001 - 12:09 am:   

Thanks guys. I'll know what to look for next time. Fingers crossed.

Steve Magnusson (91tr)
Posted on Friday, March 02, 2001 - 9:38 am:   

Eric -- sorry to hear about your problem. If it happens again, these may be a couple of things that you could try on the spot in your street clothes to aid the diagnosis:

1. In addition to just checking the water temp gauge at shutoff, and if the water temp is indeed shown high, try turning the ignition immediately back to the "on" position (engine stopped) and do a quick visual to confirm that the electric radiator cooling fan(s) is/are actually "on" (or not). If not, either: A) something in the fan stuff is bad, or B) something is preventing coolant from actually circulating thru the radiator -- which leads to the next point...

2. To test Kelly V.'s suggestion about thermostat troubles, check the radiator and/or front radiator hose temperatures with your hands (but be careful -- using the same kind of care you'd use to test to see if a clothes iron is hot). If the thermostat is "stuck", it will recirculate the coolant in the engine only so the radiator will be significantly cooler than the engine (consequently, the radiator fans never come on because the temp switch located in the radiator never gets hot enough even though the engine is quite hot.)
Herbert E. Gault (Irfgt)
Posted on Friday, March 02, 2001 - 4:54 am:   

If anyone does not know, each pound of pressure that a radiator cap holds increases the boiling point by 3 degrees.
BretM (Bretm)
Posted on Thursday, March 01, 2001 - 9:02 pm:   

Stock 308 cap pressure is 12lbs. I would consider jumping up to a 14lb cap first and see if you get a little better results. I wouldn't really suggest making any great jumps because the cooling system is designed so that the lower the pressure cap the harder it will be for water to boil in it. You have to remember that when you are just idling is when this feature is put to the test. When you are moving it is cooled enough to avoid dumping any, when you are idling expect to start dumping if it's a hot day. The cooling system on a Ferrari is gigantic anyway, two liters isn't really that much when you think how much is held in those two lines running from the front of the car, the amount held in the engine, in the radiator. The cooling system on a 308 holds 22 liters according to the owners manual (so I would say it holds at least in the 16-17 area), 2 liters isn't that much. Sometimes when I sit and idle I will dump some coolant (I always top it off at home so I expect it release some in cases like this). The factory sets things at certain tolerances for a reason, and although often times they are over cautious for reliability reasons I would stay in the ballpark of their figures.
kelly vince (Tofosi1)
Posted on Thursday, March 01, 2001 - 7:35 pm:   

The last time I had any vehicle dump coolant it was because the Thermostat was stuck, when the temp. got high enough it opened letting all the hot water out. This opens the cap and flushes out the over flow tank. Check your thermostat. It may be bad. Goodday
'75 308 GT4 (Peter)
Posted on Thursday, March 01, 2001 - 6:47 pm:   

It could, but reassure that your hoses are still good and check hose clamp tightness (don't over-tighten). I wouldn't use tap water when mixing antifreeze, distilled water is absolutely clean and won't harm the aluminum (tap water has too much minerals and crap that would help with corrosion).
Eric de Back (Eric328)
Posted on Thursday, March 01, 2001 - 6:09 pm:   

That'll increase the load on other parts of the plumbing won't it?

William Hubbell (Countachxx)
Posted on Thursday, March 01, 2001 - 5:27 pm:   

u can fix that by simply adding a 15lb water cap to the radiator. I think the 308 normally uses a 10lb cap, whatever it is, just increase the pressure loading capability by 5# & no more peeing coolant
Eric de Back (Eric328)
Posted on Thursday, March 01, 2001 - 5:02 pm:   

On a particlarly hot and humid day in Sydney (Oz) yesterday my '89 328GTS decided it would dump excess coolant (later I figured about 2 litres) onto the road. The car was idling, the aircon set on max and eveything seemed sweet, when all of a sudden I saw big clouds of white vapour in the rear view mirror. I immediately switched off the engine (sadly I didn't check the engine temp) and got out expecting the worst when I saw a huge puddle of coolant the road and steam coming out of the pressure release tube under the car. My mechanic seems at a loss to really diagnose any problem. 2 Liters, almost half a gallon I think seems excessive, doesn't it?

Any one else having this "problem"? Do you worry about the type of coolant BTW? I hear there are pre-mixed coolants, concentrated coolants, distilled water and obviously tap water.


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