[Guest]

Thought I fixed this problem w

Thought I fixed this problem with a thorough bleed of the radiator, but I get no heat from the heater cores at idle. Once engine revs are up to 1500 or more, no problem, tons of heat...like in HOT. But, stopped at a light, the heat will slowly go cold...once I start off, heat again. I have had the car for 1.5 years, and it has always done this for me. Car has new water pump and radiator was "rodded out" and cleaned. Perhaps the heater cores have a mild restriction? Just weird that once the revs are up a little, the cores pump out a TON of heat, even at the lowest settings.

My friend says he has the same problem with his 328 and 512TR.

Anyone?

 

[Guest]

Dave,
Short of having a low c

Dave,
Short of having a low coolant level, or still some air trapped in the cooling system...there's really not much else that comes to mind that will cause this problem.

The water pump isn't very efficient at idle...so if the idle speed was a bit low, this would only accentuate the problem.

My BB, as well...doesn't make great heat at idle, but becomes quite hot once rolling. As every component is new, I just attributed the modest heat output at idle as just a "normal" part of the ownership experience.

Regards,
David

 

[Guest]

Hmmm, my previous 78 308GTS di

Hmmm, my previous 78 308GTS didn't do this...and the idle is set right at (an indicated) 1k rpms.

I had my mechanic bleed the system twice, then I did it, per JRV's procedure, and did get more air out...I am wondering if there is still a pocket of air in there still?

 

[Guest]

Here's my idea:
Not sure

Here's my idea:
Not sure about the 328, but the Mondial 3.2 has an electric boost pump for the hot water to the heater. A failure would be most noticible at idle.
look at this

 

[Guest]

Now THAT is interesting! I wi

Now THAT is interesting! I will look into this, and check the diagrams. Thanks.

 

[Guest]

Boost pump, eh?

I guess the

Boost pump, eh?

I guess the BBs weren't subject to those "modern convienences", but what a great idea!

 

[Guest]

Checked the diagrams of both

Checked the diagrams of both the cooling system and heating system on the Ferrari UK spare parts link on the Ferrari Owner's Site, no luck. No picture of such a pump, and nothing described as such. Damn!

 

[Guest]

A hose comes off the port &#40

A hose comes off the port (flywheel) side of the rear bank and runs into a small electric pump.
Yours may have it, so check the engine compartment.
Of course, you could always install one.

 

[Guest]

Nope, there isn't one...I

Nope, there isn't one...I know there isn't, that's why I checked the factory drawings, thinking maybe it was removed, but it is not part of the 328....yes, I could add it. I will look at the drawings of the Mondial now.

 

[Guest]

I looked at the Mondial 3.2 dr

I looked at the Mondial 3.2 drawings both for the heating system, and engine cooling system and no such "booster pump" or any electric pump as you describe is seen in either in the engine compartment or the forward comparment up front. Could you possibly post a picture of this part?

 

[Guest]

You know - the pump IS illustr

You know - the pump IS illustrated in my Mondial 3.2 parts book. I'll somehow get pictures and numbers to you this evening. It's on the tavola with the water pipes and radiators.
The pump in on the port side of the engine compartment.
more later
rt

 

[Guest]

Hmmmm, looked again, all I can

Hmmmm, looked again, all I can find is the usual belt driven water pump. I am very intersted to see this.

 

[Guest]

In the photo, you are looking

In the photo, you are looking straight down - you can see the orange oil filter and the rear bank distributor cap; I have placed a white towel under the pump to bring it out more.

Mondial 3.2 parts book, Ottobre 87:
Tav. 23 Cooling system
#79 - part 61787900 - pompa ricircolo aqua - recirculating water pump

hope this helps
rt

 

[Guest]

One more thing - according to

One more thing - according to my parts book ALL Mondial 3.2s had this pump to run hot water to the heater. The water leaves the heater and rejoins right at the radiator.
Seems weird that whatever drawing you saw did not have it.
Of course, the accuracy of Ferrari factory literature.....

 

[Guest]

Okay, looked again, more close

Okay, looked again, more closely and see something described as "water pump kit" with a part #70000900 that supercedes 61787900 (perhaps they don't sell the pump anymore, and just a rebuild kit/either way, the drawing is very poor). Still a bit confused by it. I can see where this would help at low engine speeds, but what happens when you rev it up? Wouldn't the pump impeller then impede the flow?

 

[Guest]

Great question. Not sure of th

Great question. Not sure of the pump design - if it is an impeller it will probably not impede flow functionally enough to make a difference to the heater core if the pumped volume is already sufficient in the parallel heater circuit.

While the mondial has the one heater box a bit further away than the 328, I would have thought this aux pump would have been used on the 328 as well as it still uses that funky twin box arrangement which looks like it would need a boost.
I can say the Mondial system works well.

If the heat is low on both sides, then you know the flow problem is proximal to the t fittings (i.e. kinked or failed hose)or unlikely event of both heater boxes failing simeltaneously. I'm not sure what that diverter valve does shown on the parts drawing, but it looks like the design type that goes wompus on the Kjet also.

Will be interested to se what you find.
best
rt