bogus wrote:
I am not done, yet... but...

There is a heater line restrictor that feeds the heater core and controls flow.

This little plastic cylinder doesn't last forever... mine lasted 24 years and 214k miles. Mine had, apparently, been weeping for sometime... became a full on leak last week. It only takes 10 minutes to swap.

I will post a pic of what my dead one looks like, but in short, the nipples on the in/out flows were all but gone.

A new one is about $20, shipped, from RockAuto.com.

pianoguy wrote:

Don, I'll bet you won't have to worry about replacing the $8 part until you're at least 100 ;-)

donhall wrote:
I posed my question about cause of part deterioration before I learned it
was plastic. I'm sure any plastic will become brittle with time, but, now, I'm
interested to know if proper coolant maintenance might have prevented the
eroded nipples?

Andy, was the coolant changed as required?

Note: I ordered the $8.00 part from RockAuto. At 84, I'm not concerned with
longevity.

bogus wrote:
It is plastic... but it is in a hostile environment.

I don't think coolant condition would effect plastics as much as it effects metal. There isn't the same chemistry.

Think about it... plastics are more effected by temperature changes than anything else. Toss in the corrosive effects of coolant, under pressure, erosion is going to happen.

Coolant lives near boiling point. That can't be good... when a part is exposed to such an extreme range - below zero all the way up to 230F.

This is simply a replacement part. There is no avoiding it. And as these cars age, this is a likely replacement.

I decided to go with the GM part because the last one lasted. I don't know if the other brands use the same plastic, and I don't want to risk the part blowing apart at some point.

BillH wrote:
A $0.05 piece of copper tubing will do the job if you don't plan to use the heater muck.

donhall wrote:
Quote:

BillH wrote:
A $0.05 piece of copper tubing will do the job if you don't plan to use the heater muck.

Agreed, Bill......my concern would be with the function of the part....'restrictor'.

What does that part do? Something happens in the barrel of that part.
I will soon learn.

bogus wrote:

I decided to go with the GM part because the last one lasted. I don't know if the other brands use the same plastic, and I don't want to risk the part blowing apart at some point.......

BillH wrote:
[quote]

Don, that part is just a flow restrictor to slow down coolant flow thru the heater core so more heat can be extracted in the heater box. It's just a plastic tube with a smaller hole in it...........

donhall wrote:

Andy, out of curiosity, I searched numerous sources selling this part (74795).
All sites searched (15+/-) showed Four Seasons as the supplier/maker(?) of this part.

No site suggested/mentioned ACDelco. It may follow that ACDelco just puts this part in their box, as they do with many parts, and increases the price (?).

I'm not recommending a part, just passing along some basic info.

Right you are, Bill...... my part arrived from RockAuto today, and the IDs of the
hose nipples are ½", and the inside hole diameter is 3/16". As you suggest, it is just a plastic tube with a smaller hole located in the barrel.