What year is your car? The steam pipe return and throttle body coolant routing is different,

#4 in the picture in post #6 is the connection for the oil cooler. Not all F-Body LT1 engines have the oil cooler. In cars without the cooler there was a bypass hose to the lower radiator, but you appear to not have that connection.

The radiator connection below the fill neck is for the steam pipe return. The factory radiator has a “liquid vapor separator” according to the literature. In deleting the TB coolant, be sure not to block the steam pipe return. Shoebox indicates the solution in post #7.

1993-1994 Routing:

http://shbox.com/1/93-94_hoses.jpg

1995-1997 routing:

http://shbox.com/1/95-97_hoses.jpg

 

It's a 95 Trans Am. The replacement rad looks like it would fit fine, it just doesn't have the oil cooler fitting or the steam pipe return.

 

Could I get away with capping the oil cooler fitting with my 95 TA?

The steam pipe comes out of the head on the passenger side? I can T that into a return line to the rad?

Thanks for your help. I figured it would be more straightforward. I suppose it would've been if I went with OEM!

 

Theoretically the steam pipe could tee into the return line. How that impacts “vapor/liquid separation” I don’t know. I can’t see any downside of blocking the oil cooler pipe. But I've never tried either, so I can’t say with exact certainty. I bought a Griffin aluminum radiator, manual trans version, with all the factory connections.

 

Perhaps the best place to tie in the steam vent line is in to the line that goes to the overflow tank, they're both on that side anyway.

I'd rather keep the oil cooler coolant flowing so I think I'll tie that in to the big return line near it.

Thanks again for your help!

 

Will update on the results

 

No…. do not tie the steam line into the overflow line to the reservoir. You'll eventually dump enough of your coolant into the reservoir and it will overflow.

 

No eh? My rational was that the steam pipe originally goes through the TB and then returns to the rad next to the tube to the overflow reservoir.

 

Note to anyone replacing a radiator on these cars. Do your homework first and don't get ***** deep trying to jury rig

 

The overflow line from the radiator cap neck is “outside” the radiator, isolated by the pressure and vacuum relief valves in the cap. When coolant heats up and expands in volume, and pressure exceeds the cap rating (18 PSI) the cap seal disc rises against the spring pressure and allows excess coolant to flow from the radiator to the reservoir. As the radiator cools and the water mass contracts, it pulls a vacuum on the cap, a second disc drops against its spring and the vacuum pulls coolant out of the reservoir to keep the radiator completely full.

Put a tee in the overflow line and steam/vapor/liquid coolant entering the tee could go either way. But the flow toward the radiator is blocked by the cap valves. On the other side of the tee, headed for the reservoir, there is no back pressure, and the coolant coming from the steam pipe at high pressure - pump discharge pressure minus flow losses through the block and heads - takes the path of least resistance into the reservoir. That coolant is lost from the system, reducing performance of the cooling system, and could overflow out of the reservoir, and not be available to refill the system when the radiator cools down.

 

There is no harm in blocking off the oil cooler hose port on the water pump. The F-body is the only one that actually used it. It is blocked off on both the B and Y body cars.

You can connect the steam line to the large return line to the radiator by using a 93-94 style hose (see #14 in diagram below) or a 95+ hose with a tee in it. Read information about tees on this page:
https://jagsthatrun.com/collections/...-radiator-hose

 

She's back together and purring like a lion. Capping the bypass & teeing the steam vent worked great, thanks for all the help folks!

 

Thanks for following up and letting us know what worked.

 

I've a new problem and it could be related..

I'm getting a check engine light and the cooling fans turn on after about 5 minutes of driving. The temp Guage reads about 1/8-1/4 up the scale and never gets higher then 1/4.

I figure it was the ect sensor in the water pump. Replaced and no change.

The car ran fine for about a month after the rad change. Then the fuel pump went and it was about another month before I replaced that and was back on the road. Recently there was a barf of coolant on the garage floor under the water pump area.

I thought it was my homemade T fitting for the steam pipe into the coolant return but that's holding fine and there's been no coolant barf since..

Any thoughts?

Thanks

 

Did you check for codes?