i have a 86 iroc 5.7 tpi.....engine has been completely refreshed. drive around town with no prob. but get on highway and temp goes up around 240..aftermarket temp gauge. Also low oil pressure. coolant fan is wired direct....anyone have any ideas??

 

how low is the oil pressure, and what oil and weight are you running? what do you mean by refreshed? is the coolant clean, and what mixture is it? is the air dam under the nose still in place?

 

oil pressure varies on highway between 10 and 20 pounds. around 5-10 psi in city. using 10-30 oil. refreshed meaning all gaskets replaced. 50/50 mix on antifreeze. i believe the air dam is still there. why? i was thinking of throwing a quart of 20-50 in it to thicken it up. oil pump was replaced with high velocity at time of tear down. the only thing i can think of is my fan running full time is counter balancing air through radiator.

 

The air dam grabs air and directs it up through the radiator while on the open road, and in traffic, it doesn't. No, the fan isn't going to counteract the incoming air.
Your oil pressure is awfully low, but do you know your gauge is accurate? If your pressure really is that low, I would throw in some thicker oil, at least 2 quarts of 20w50.
Check your ignition timing too. If it's off by a bit it can make the engine run hot.

 

Check if air dam is in place and make sure the fan is not running at highway speeds. Example: my oil pressure with the stock gage if between 35/40PSI at highway speed. What is your pressure at start up??? Should be up to 60 PSI otherwise you have problems and heavy weight oil is not the solution.

 

Ditto above. 5 PSI at idle is dangerously low. Thats with a high volume oil pump? Either something is clogged or you have some major issues. You dont want to hear it....but you need to verify that oil pressure.....and if it is indeed that low, you are going to HAVE to pull that engine out. Look, you gotta do this ASAP. I ignored this very same problem (my PSI was almost identical to yours) I drove the engine for less than 50 miles before I spun a bearing and thrashed a nice 4 bolt block.

 

i get around 18 psi on start up. air dam is in place. it was supposed to be a high pressure oil pump. i had less oil pressure before i adjusted the valves. i'm running around 18 psi at 2500 rpm. i need to adjust my timing it is way to advanced. anyone got a timing sight for me?? i have pics of my car now but not sure how to upload them.

 

my fan is direct power. cant shut it off on highway

 

Don't worry about the fan being on while running down the highway. It's NOT going to hold back any of the natural wind that will be passing through your radiator. The old belt driven style fans that ran all the time is proof that having yours run is not a blocker. And technically, your engine shouldn't even need a fan on the highway.
For your oil pressure, it would be a very good idea to either hook up a mechanical oil gauge so you know for sure what the engine is putting out...or not, or start by replacing your oil sending unit. They can and do go bad.

 

Then your timing is responsible for the overheating. If you are too far advanced, you can melt your engine....seriously. I made the same mistake, but I caught it before any damage.

Please, verify that oil pressure. Your going to spin a bearing. Its not pretty. Ill never forget what a spun bearing sounds like.....