Coolant bypass restrictor

[alfa_chan]

I heard about the Coolant bypass restrictor on a thread in the Spider forum and did some research, find this page -

http://www.geocities.com/motorcity/d.../bypassco.html

After reading it, it made me more confused.

Is the restrictor a "replacable part" like a thermostat? (I cannot find it on IAP) How does it look like? Where should it be (inside the manifold, underneath the thermostat)?? How can I tell if it's still on my car?

Please help. Any comment is appreciated. Thank you


Didn't drive my GTV for the last two days before it was running 15 degree above the baseline on freeway.

Want to make sure everything else is working before bringing the car to a radiator shop to clean the radiator. Don't want to flush the radiator again. (It's a hassle to bring the coolant to those stupid recycling events)

While I know my temp gauge is not accurate at all, will my GTV still running hotter than usual because it has an aftermarket header and high-compression pistons?

[67GTV]

Quote:

Originally posted by alfa_chan Want to make sure everything else is working before bringing the car to a radiator shop to clean the radiator.

[John M]

I am not sure where it is on a GTV, but on the Spider the restrictor is actually in the lower short hose that runs from the thermostat housing to the pump on the front of the motor. Its the hose that is very close to the distributor.

On the heat from high compression/headers/etc, its been my experience that your car will not run hotter and require a different radiator (providing yours is still good). I do use an electric fan w/ on-off thermostat, but that is more performance driven rather than for cooling. Unless you are turbocharging/supercharging your car, the stock radiator is adequate enough to let you run normal temps.

Best Regards,
John M

[Keven]

alfa_chan,

I agree with the last post about pulling
the radiator yourself, cheaper, and peace
of mind that it was done right.

When I rebuilt my spider with 10.4istons,
and headers, I had a 4 core radiator put it,
and never ever overheated, even when doing
90mph up the Grapevine in the middle of the
summer

I think I paid something like $160 for the
new heavy duty core, which added about 1 gallon
more cooling capacity. Totally worth it.

As far as the restrictor here is a nice write up:

http://www.geocities.com/MotorCity/D.../bypassco.html

Its in the hose, and I dont think its worth trying to
change, just buy a new hose with one in it.

[alfa_chan]

Thank you Kai

I am just going to take the car to the radiator shop and let them clean (no re-core) the radiator, do they still have to take the radiator off? If so, I better call in first and ask for a quote. If it's like a $100, I might just as well go for a new Alu radiator that I might be able to get cheap.

Quote:

Originally posted by 67GTV A little tip to save some money. Take the radiator out yourself and bring it to the shop. There's an over-heating discussion in the Spider forum that mentions this.

[alfa_chan]

Thank you John & Keven

Oh I see, it's in the hose. When I change my head gasket, I ordered all the new hoses from IAP, including the bypass.
However, they said the manufacturer had discontinued it, that's why I changed everything except that one. Gotta call Centerline or AR Ricambi.
---------
This is the post that made me wonder about the restrictor.

Quote:

Originally posted by Keven As far as the restrictor here is a nice write up: http://www.geocities.com/MotorCity/D.../bypassco.html Its in the hose, and I dont think its worth trying to change, just buy a new hose with one in it.

[67GTV]

Heimeng,

You really do want an aluminum radiator, huh? I think someone here said they're only useful for racing. Would be overkill for a street car.

As far as cleaning vs. re-coring, I believe a shop would need the radiator out of the car for this also. I think they even need the radiator out to pressure test it. From what I recall (it's been a while) a rad. shop will disassemble the radiator, taking the top, bottom and sides off. Then they'd dip the core in some caustic crap. A little pokey pokey with some long rods. Then they'd re-braze all the pieces back together and shoot it with black spray paint. I've always had good luck going to areas like Wilmington where there are many radiator shops. Competition keeps the prices in check. You might look around for a similarly automotive industrial area around you. Look for lots of junk yards, tire shops and radiator shops.

I seriously would take the radiator out myself. You will be much more careful in removing it than a shop would. It shouldn't be too much work and you can take the opportunity to clean up any leaves and dirt around in that area.

[alfa_chan]

Haha!!

It's more about the $$$ situation I'm in right now. I can get those alu radiator pretty inexpensively, how inexpensive? I don't know yet.
The cost of cleaning, new coolants, and recoring might cost more than just put an ALU in it.

When I get back to the warehouse today, I will go out and get some quotes. There is quite a lot of junk yard, auto shop and radiator shop in El Monte.

I will definitely get the radiator out myself, the GTV is by far the easiest car I have worked on.
When the radiator is out, I will have more space to work on the alternator too

Quote:

Originally posted by 67GTV Heimeng, You really do want an aluminum radiator, huh? I think someone here said they're only useful for racing. Would be overkill for a street car.

[papajam]

A look thru the parts books revealed absolutely nothing about the bypass hose restrictors. It wasn't there (or I couldn't find it). Perhaps they came with the hose when purchased from Alfa but not the aftermarket? Never having seen a restrictor in any Euro 1750, and having seen numerous restrictors in US 1750 and 2ls, leads me to believe that they're a US market nightmare only. Plus, the bypass hose, 105.51.01.628.00, is a US market part number. But why only the US? So the heat can be turned on faster in the winter for the fluffy Americans? Who knows.
Both the Euro and US thermostats, however, appear to be the same and carry part number 105.41.01.064.00. The pictures show that the stats have a disc on the bottom. Now, not wanting to redesign Alfa's cooling system, it would seem to me that if the Spica intake manifold has the machined surface to accept the stats disc, then the restrictor can be skimmed across the pond.
FWIW, the Euro 2l engine (w/o restrictor) that was in my 1750, with hi comp pistons, head work, VERY hot cams, headers, etc. could idle for hours in 100 deg temps with 100% humidity and never see the high side of 180 deg F. And it has a stock radiator with a Euro thin blade plastic fan.
IMO, converting to an electric fan is just masking a cooling system problem and could even make an overheat condition worse if the fans installed as a pusher on a system designed as a puller.
The stat in the pic is made by Gates. P/N 33208 (I think).

[alfa_chan]

As far as I remember, the thermostat that I got from IAP has the same disc on the bottom. I just went out and take a look at my GTV, there is nothing in the bypass hose.

Centerline listed two different hoses for the bypass hose, one for US car (cheaper) and one for Euro spec (more expensive)

Quote:

Originally posted by papajam The stat in the pic is made by Gates. P/N 33208 (I think).

[papajam]

Quote:

Originally posted by alfa_chan Centerline listed two different hoses for the bypass hose, one for US car (cheaper) and one for Euro spec (more expensive)

[alfa_chan]

Quote:

Originally posted by papajam The US hose is pretty much straight while the Euro hose has two molded 90 deg bends in it.