schmol

Hi guys, just wondering what is the difference between the s4 and the s5 radiators? I'm asking this because I have a '89 S5 vert and my pressure cap is in the middle of the radiator and I have '90 GXL which is also a S5, but it has the cap on the far right sitting on a long neck that points towards the engine.

My vert's rad is leaking at the very bottom of the fins area and went to salvage the other rad out of the GXL and noticed the difference.

RotaryResurrection

iTrader: (8)

The 86-87 stock radiators have no cap anywhere, and the cap and overflow fittings are on the engine.

The 88 stock radiator has the cap in the center as well as the overflow, and the fill cap on the engine as well. IN this case you pretty much ignore the fill cap on the radiator and fill coolant on the engine.

The above radiators can pretty much be swapped around without issue in the 86-88 cars.

The 89-91 all have the cap by the battery on an extension tube, and no cap on the engine. You must fill the radiator itself.

having an 88 radiator on an 89-91 car won't cause a major issue, but it wouldn't fly for me...since the cap on the 88 rad sits lower than the engine's thermostat neck, it means there's likely to be air trapped there, or in other words you can never completely fill the system unless you do so with the car on an incline with the back of the car at the bottom of the hill.

Even then, when you take the cap off to check the level (on level ground) some of the coolant will run out.

Get an 89-91 radiator.

schmol

Thanks for the info Res, I think I might have a after market rad as mine cap is in the center of the rad with the overflow coming off that. I also have no filler cap on the engine and have to use the cap on the rad to fill it. Or maybe they swapped the original s5 rad for a s4 radiator sometime ago.

It's a small leak, so I'm gonna try some stop leak for now until I can get it to a shop for the fix.