this sounds like a stupid question for me, but my background is in air-cooled flat four engines, not water cooled V8's..

Engine is a SBC350, I know, I know. I didn't do it, previous owner did...

Engine temp after like 15-20 minutes of driving is around 180F or so, but after about 30 minutes of mild driving around town, it starts creeping up.. hangs out at 200 for a little bit, then creeps higher..

Oil level is fine and no evidence of coolant in the oil, so I'm fairly certain it's not a head gasket issue.

Decided to check the thermostat because that seemed like the next easiest/cheapest thing to check.. there was NO thermostat installed. so I dropped a 180F thermostat in it.. Doing the same thing.

Radiator has a big electric fan on the rear side of it, it's fully functional..

On the front side, it has an AC condensor and I believe a trans cooler. Could those be blocking too much of the airflow through the front?

I'm not sure what I should be doing/looking at next, so again, sorry for a question that is probably super basic knowledge, I'm just out of my element..

 

Is there a shroud? have you checked the radiator with the cap off to see if the coolant is flowing through the cores? Is the fan a pusher or puller? And how many cfm is the fan? Does the temp rise when you are at a stop light or going down the road?

 

no shroud, large (maybe 15") electric fan on back and smaller (maybe 10") electric fan on front. both operating powered on all the time.

no idea of the CFMs, temp rise seems to be independent of movement (doesn't matter if I'm sitting still or rolling, it happens..)

last night, I pulled the radiator cap and let it run for a few minutes to try and "burp" out any trapped air.. it almost emptied the puke tank, so i refilled it and it still does the same thing..

The coolant in the puke tank was a nasty combination of green and brown, so I just drove it down to a shop to have the radiator pulled, cleaned, and the entire system flushed.. truck has sat for an unknown number of years, so i'm hopeful it's just **** in the radiator that's now moving through the system and clogging things up, and the clean/flush will cure it..

 

Fan shroud is really important. Without a shroud the fan only pulls air in front of fan. With proper shroud it pulls air through entire core. If you have two fans, front and back, make sure they move air in same direction not against each other.

 

Here's some shots.. i thought the shroud only really did anything with a crank mounted fan?
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I'm a retired HVAC tech not an auto mechanic. I know moving air through coils. I don't think what you have will work unless radiator is really oversized. If you want to run electric fans I would try to find a two fan set up that covers entire radiator The guy that removed thermostat had an overheating problem.

 

I was thinking the same. I was kinda concerned that having the condenser and trans cooler mounted on the front, blocking like half of the radiator might be restricting too much airflow as well..

This is just how it came.. like I said, mother in law being over charged by an unknown shop in NorCal for all the work (she claims she spent like 30k getting the engine swap, front suspension swap, AC, and interior and other stuff.. From what I've seen, I might have spent maybe 12k including the cost of parts.. lol)

It has been sitting a LOT over the last decade or so, so I'm totally ok paying to have the cooling system cleaned and flushed first, but yeah, will probably better airflow as well..

 

The coils in front should not be a problem. The fan inside if pulling air through radiator will only pull some air through the area on front. Since it isn't against the rad or shrouded some of the air will be pulled from around the fan as there is less resistance than pulling through the core. I don't know if aftermarket fans are available for your radiator. Is it a stock Ford radiator? Maybe something for a y block. Looks like lots if room. Maybe make a shroud and mount fan to it.

 

I don't know the make/model of the radiator, I'll look for marking when I get the truck back.. it's aftermarket, but I don't have any specifics.. the engine is a sbc350..

Are you talking about a shroud in the front to direct air into the fins instead of allowing it to go around?

 

You said there is a fan on the back side of the radiator, so you should be looking for a shroud like the photo below. Might be worth confirming that the fan does indeed pull and not push. I don’t have a lot of experience with electric fans but I’m sure a shroud would improve cooling as it helps a lot with a mechanical fan.

 

Shroud between radiator and fan.

 

I'd try to go back to an engine driven fan if possible - looks like there's enough room for one. You might be able to find a shroud that would work at a salvage yard. I know the stock y-block didn't have a shroud, but the SBC that's in there now is larger & would require more cooling capacity. On a side note: I run electric fans on mine due to clearance issues. I bought a radiator/electric fans/shroud package from Champion radiator similar to this setup: https://www.championradiators.com/Fo...roud-1968-1979. Worth noting that mine will still heat up with agressive driving on hot days.

 

I get the measurements when I get the truck back and look for something like that that will fit.. seems like a good idea.. haha

 

This image shows better what I tried to explain. The shroud seals around radiator so all the air the fan moves is drawn through the radiator. Air is fluid and will go around the condenser in front. Sometimes even better. A friend mounted a spare tire on front bumper and his truck ran cooler.

 

If the problem exists while the truck is moving, at normal road speeds, say over 35mph, then the fans are not the problem. There may be room to improve on the fans, but they are not the problem.

If I'm not mistaken, reverse rotation water pumps are available for sbc, I think originally for serpentine systems but I don't know exactly how interchangeable they are. If you observe coolant flow through the radiator with the cap off, you should see coolant flowing from the top hose and that will confirm that flow is correct.

If you can temporarily relocate the trans cooler or ac condenser, for trouble shooting, try it and see if the problem improves. While this is not particularly uncommon on modern vehicles, it does not mean that it can't be the problem on a vehicle that was never equipped as such.