I started replacing the coolant hoses on my `88 Iroc TPI and found some I had never seen on other cars before. I found 3 metal tubes(5/8-3/4) on the passenger side. One on the frame rail that goes to the heater and two that seem to go to the factory sandwich adapter above the oil filter which I assume is for the oil cooler. I don`t understand how this system works because the radiator on my car was replaced a few years ago and there is no hook-ups on it for an oil cooler. The two metal tubes that run under the engine to the oil filter has coolant in them so where does the cooling take place? I checked my `88 factory manual which shows oil cooler connections on the stock radiator but mine does not have them. I am disabled and can not get under the car to check this out so I am going to stop by a shop this week and get the car up in the air so I can check it out. Also, there is what looks to be a vacuum line that connects to the top of the heater control valve that is broken, are these available new? Any information will be appreciated, I am totally confused, my natural state these days.

Does anyone know how this cooling tube system is supposed to work? Before I finish filling up the coolant, I would like to bypass the 2 side by side tubes that go under the engine, I read some old posts that some models used 2 short pieces of short 3/4 heater hose to connect to the sandwich adapter above the oil filter and some models omit the hose and the pipe connects directly to the adapter. If it has hose it is probably original and I don`t feel comfortable driving up 395 to Reno in this heat with 2 old hoses.

from what ive been told, the factory oil cooler does not have the typical remote cooler on the radiator. the cooling is done with coolant flowing through the sandwich adapter above the filter.

Thanks for the reply. I finally found a little info in some old posts. Given that this oil cooler system is 20 years old and the tubing is severely corroded I think it`s time to replace it with a newer model. I assume the sandwich type heat exchanger/adapter is also ready to fall apart due to corrosion.Thanks again //<86TA>\\