so i bought this s10 with a small block 350 in it. it overheats on idle and has low oil pressure on idle. the oil pressure goes from 50 psi cold to around 10 hot on idle and the temp reaches 210 220. the coolant actually boiled out of the radiator once.it stays around 190 driving 55. it has a two barrel carb. it has a shroud and flex fan. i did a coolant flush and come to find out that the radiator is mostly cooling the oil. when i filled the radiator back up it only took about half a jug of coolant and less water than that. the truck also has a kit to move the oil filter up top for easy changing. my question is why would the radiator be used to cool the oil? could that be my problem? also when i step on the gas i get spudering at higher rpm. im new to bigger motors and dont know much about them. i really like the truck but i dont want a dumper. please help me and im new lol
jeffreyminten
Check air flow, could be clutch fan bad. 10 psi at idle is a little low but not awful. 10 psi every 1000 rpms is a basic rule. If you had a light in it, it would never come on. Switch to 20W50 if you are worried after you fix cooling problem.
Stock 4 cylinder and 6 cylinder radiator has an engine oil cooler in it, as a means of ensuring more even coolant and oil temperatures in all operating environments....but that stock radiator is almost always going to be too small for a V8 transplant.
Sounds like you will need a bigger radiator that does not have the oil cooler in it, and adding a separate engine oil cooler out in front of the radiator if you want or need to keep that cooling provision.
If it is just a cheap aftermarket flex fan, it could also be the problem, and maybe most of the problem since you said it cools fine at speed, but overheats at idle or low rpm....get the correct clutch fan for the application. Flex fans are one of the biggest complaints we see here at Hotrodders, half the overheating threads in Today's Posts mention they are using one of those POS.
Sounds like you will need a bigger radiator that does not have the oil cooler in it, and adding a separate engine oil cooler out in front of the radiator if you want or need to keep that cooling provision.
If it is just a cheap aftermarket flex fan, it could also be the problem, and maybe most of the problem since you said it cools fine at speed, but overheats at idle or low rpm....get the correct clutch fan for the application. Flex fans are one of the biggest complaints we see here at Hotrodders, half the overheating threads in Today's Posts mention they are using one of those POS.
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. X 2... flex fans don't work as well as a stock fan with silicone clutch... they even flatten out and block airflow at high RPMs... also need proper radiator air shroud around the fan... are you running a manual tranny? Rev the engine and see if lower radiator hose sucks flat...
. X 2... flex fans don't work as well as a stock fan with silicone clutch... they even flatten out and block airflow at high RPMs... also need proper radiator air shroud around the fan... are you running a manual tranny? Rev the engine and see if lower radiator hose sucks flat...
You can't cool a 350 V8 using either the inline 4 or any of the V6 radiators they are simply not large enough. Cooling the S10 at idle and in stop and go traffic will be a problem even with conversion to a V8 radiator as no matter the fan choice things are packed so tightly in the engine compartment that it is difficult to get airflow around the engine and out of the engine compartment.
Some models of S10 included an oil to coolant heat exchanger in the radiator on the drivers side return tank. This is intended to warm the engine up faster by heating the oil with the warm coolant. It is effective in this regard. This gets the engine off cold start mixture enrichment (choke) quite quickly which reduces emissions and piston, ring and cylinder wall wear. Any affordable fix will probably have to forego this feature. So the adapter on the oil filter boss of the block will have to be removed.
There are 2 radiator solutions that don't cost your life's savings:
This is aluminum 3 tube 2-1/2 thick core of 16-5/8x26-3/8 inches overall is 18-5/8x33 inches
1983 Chevrolet Malibu ALL ALUMINUM RADIATOR ALL10743X8162-3AA 5.0L V8 305 | All Aluminum Radiator | Chevrolet Auto Parts
This is aluminum 2 tube 1-3/4 thick core of 17x28 inches overall is 19-5/8x33 inches.
https://www.radiatorexpress.com/pro...com/product.asp?part_id=218234&aaia_id=1038776&gclid=CO31lLSToMACFQypaQodwysAHw
The filler is on an angle which provides just enough to shut the hood without having to carve the truck's radiator frame as long as you can live with a slight angle as installed with the top of the radiator leaning slightly toward the engine. You'll have to drill a couple new holes in the lower frame to move the rubber mounts out a little. At the upper the radiator has a frame. You pull its frame to the trucks upper radiator frame and insert at each side an upper radiator rubber mount with one ear cut off. Clamp in place and drill a hole through the truck's radiator frame into the radiators frame channel and secure with two 1/4 machine screws and a nyloc nut.
You can stand the radiator up but that requires notching the truck's lower radiator frame such that the radiator stands on what is the bottom of what had been a boxed beam. This is safe there is sufficnet strength in that lower radiator frame that making it into an L section for the length of the radiator does not compromise it. If you do this then you need a set of radiator mounting brackets that reach over the radiator's upper frame to clamp it to the truck's radiator frame.
You will need to build a shroud this kit gets you well started:
Aluminum Fan Shroud Kit for 31 Inch Radiator, Engine Driven Fan - Speedway Motors, America's Oldest Speed Shop
Bogie
Some models of S10 included an oil to coolant heat exchanger in the radiator on the drivers side return tank. This is intended to warm the engine up faster by heating the oil with the warm coolant. It is effective in this regard. This gets the engine off cold start mixture enrichment (choke) quite quickly which reduces emissions and piston, ring and cylinder wall wear. Any affordable fix will probably have to forego this feature. So the adapter on the oil filter boss of the block will have to be removed.
There are 2 radiator solutions that don't cost your life's savings:
This is aluminum 3 tube 2-1/2 thick core of 16-5/8x26-3/8 inches overall is 18-5/8x33 inches
1983 Chevrolet Malibu ALL ALUMINUM RADIATOR ALL10743X8162-3AA 5.0L V8 305 | All Aluminum Radiator | Chevrolet Auto Parts
This is aluminum 2 tube 1-3/4 thick core of 17x28 inches overall is 19-5/8x33 inches.
https://www.radiatorexpress.com/pro...com/product.asp?part_id=218234&aaia_id=1038776&gclid=CO31lLSToMACFQypaQodwysAHw
The filler is on an angle which provides just enough to shut the hood without having to carve the truck's radiator frame as long as you can live with a slight angle as installed with the top of the radiator leaning slightly toward the engine. You'll have to drill a couple new holes in the lower frame to move the rubber mounts out a little. At the upper the radiator has a frame. You pull its frame to the trucks upper radiator frame and insert at each side an upper radiator rubber mount with one ear cut off. Clamp in place and drill a hole through the truck's radiator frame into the radiators frame channel and secure with two 1/4 machine screws and a nyloc nut.
You can stand the radiator up but that requires notching the truck's lower radiator frame such that the radiator stands on what is the bottom of what had been a boxed beam. This is safe there is sufficnet strength in that lower radiator frame that making it into an L section for the length of the radiator does not compromise it. If you do this then you need a set of radiator mounting brackets that reach over the radiator's upper frame to clamp it to the truck's radiator frame.
You will need to build a shroud this kit gets you well started:
Aluminum Fan Shroud Kit for 31 Inch Radiator, Engine Driven Fan - Speedway Motors, America's Oldest Speed Shop
Bogie
Ok so I replaced my thermostat and now the truck cools fine runs around 190 200. Oil pressure returned. I changed the swamp slug that was in there.I installed real vacuum caps instead of hoses with screws in them and I also got new plugs wires cap and rotor and timed it around 12 on idle no advance and 32 total timing at 2500 rpm. Runs great more power than ever except now I have tons of blow by and it wont keep a steady idle and sometimes dies.I don't get it. The more I fix the more problems I have. What does that mean with all the blow by? Bad valves? Head gasket? Its only doing it on the #1side of the motor.feeling like I got a lemon.
. Make sure PCV valve is working OK, not plugged, allowing flow only in one direction... May be sucking in some oil and/or coolant... try re-torqueing head bolts including those under the valve cover... re-snug the intake to head bolts... if that doesn't work, try a compression test on those cylinders to see if blown headgasket...
let me guess non coated headers also....
a set of 85-92 t/a hood vents (there are 4 2 at nose 2 at back side corners) will let out the heat..
late model caddy truck fender extractors will help your cause also..
timing could be off also..
rubber weatherstrip between the rad and shroud helps the fan pull air through the core..
send that flex fan to ebay or craigs list..
a junk yard crawl for a factory full sized trucks oil cooler set up.. will take the oil heat under control..
but like others have posted the rad if the original to truck is to small..
but what listed above is cheap and helps even with the correct set up..
I'd also add a 3rd gen core support air dam to force the air into the core at speed.. (or build one)
just because it boiled over means nothing did you test the rad. cap?? it might not still hold 15psi (or whatever the stocker was)
also where is the temp sender for the gauge in the head or block??
underhood is no more cramped than most v8 cars from the last 30 years
a set of 85-92 t/a hood vents (there are 4 2 at nose 2 at back side corners) will let out the heat..
late model caddy truck fender extractors will help your cause also..
timing could be off also..
rubber weatherstrip between the rad and shroud helps the fan pull air through the core..
send that flex fan to ebay or craigs list..
a junk yard crawl for a factory full sized trucks oil cooler set up.. will take the oil heat under control..
but like others have posted the rad if the original to truck is to small..
but what listed above is cheap and helps even with the correct set up..
I'd also add a 3rd gen core support air dam to force the air into the core at speed.. (or build one)
just because it boiled over means nothing did you test the rad. cap?? it might not still hold 15psi (or whatever the stocker was)
also where is the temp sender for the gauge in the head or block??
underhood is no more cramped than most v8 cars from the last 30 years
350 small block S10 overheats and low oil pressure.
Don't even check your PCV valve just buy one and replace it. Check under your valve covers for baffles where the PCV valve and breather/filler cap are. If they do not have baffles install these baffled grommets. http://www.summitracing.com/parts/sum-g3428 If this doesn't slowdown the blowby you might have some worn rings. You need to set your total timing at 36 degrees. You can check your initial but just set the total. Are you saying you don't have a distributor with a vacuum advance? It is not good for everyday street driving. This is a very good article on engine timing and HEI distributors. http://www.crankshaftcoalition.com/wiki/Hot_rodding_the_HEI_distributor
Don't even check your PCV valve just buy one and replace it. Check under your valve covers for baffles where the PCV valve and breather/filler cap are. If they do not have baffles install these baffled grommets. http://www.summitracing.com/parts/sum-g3428 If this doesn't slowdown the blowby you might have some worn rings. You need to set your total timing at 36 degrees. You can check your initial but just set the total. Are you saying you don't have a distributor with a vacuum advance? It is not good for everyday street driving. This is a very good article on engine timing and HEI distributors. http://www.crankshaftcoalition.com/wiki/Hot_rodding_the_HEI_distributor
I have two chevy s10's with v8's one is a 86 and the other a 96 and I have always had problems with getting them to stay cool at idle during the summer months up here in Ohio. If I use a high flow non restrictive 160 degree thermostat it will never get over 190a t idle but once I go down the highway it will then run too cold and only be around 160 on colder days and that is no good for wear.
When I bought my 96 s10 back many years ago it already had a 350 stock vortec in it and a stock 4.3 v6 radiator in it which was a one inch plus one row and with a dual generic blower fan in front of the radiator. They had no thermostat in it and it ran 160 and was way too cold. With a 180 oem stat it did fine since it was a stock motor but still not very good overall but did not over heat but I ran the fans on a toggle switch so I always ran them in town driving.
Since my performance builds If I use a regular oem 160 stat it does better but then because it restricts more then a high flow over time it will get warmer at idle but takes longer while still being too cold down the highway. On the 86 or first syle of s10's you can cut the front support and move the radiator up front in order to clear a fan. You can fit a universal 31x16 two row aluminum radiator from summit. Some have clutch fans but with my mounts and radiator forward it still does not have enough room to clear the clutch part of the fan on my 86 or 96.
Now on my 96 s10 I cut the front support as well and moved my radiator forward to clear a fan. I use a 7 blade flex fan with a 2 1/2 depth on both of my builds as I can't fit a clutch fan as it is tight in there with radiators as far forward as they go. With a stock one row radiator like the ones for the 4.3 v6 then you could fit a clutch fan but anything performance and like stated they will not keep a performance v8 cool in stop and go traffic. The radiators listed below is what I use on my 96s10 and the other one from summit I use on my86s10.
For my 96 s10 I use a shroud for a 96 s10 with the 4.3 v6. I had to customize it some but it allows the most air to be pulled through with my fans.
Another option is I have read for electric fans if you want to go that route then use a dual electric setup dodge intrepid from 98 to a few years after that and I have read they cool pretty well. For my 96 I ended up with a 180 oem stat and a 17 inch 7 blade flex fan and it runs about 190 all the time and sometimes can get a little hot in stop and go traffic but for most part it does very well.
I have not put the shroud on my 86s10 yet as I am also using the one from a 96 s10 to put on and try and cool it at idle but have not gotten around it yet to be able to comment on how well if it works good or not.
JEGS Performance Products 52000 JEGS Universal Performance Aluminum Radiators - Free Shipping on All Orders @ JEGS
http://www.summitracing.com/parts/gri-1-25271-x/overview/
When I bought my 96 s10 back many years ago it already had a 350 stock vortec in it and a stock 4.3 v6 radiator in it which was a one inch plus one row and with a dual generic blower fan in front of the radiator. They had no thermostat in it and it ran 160 and was way too cold. With a 180 oem stat it did fine since it was a stock motor but still not very good overall but did not over heat but I ran the fans on a toggle switch so I always ran them in town driving.
Since my performance builds If I use a regular oem 160 stat it does better but then because it restricts more then a high flow over time it will get warmer at idle but takes longer while still being too cold down the highway. On the 86 or first syle of s10's you can cut the front support and move the radiator up front in order to clear a fan. You can fit a universal 31x16 two row aluminum radiator from summit. Some have clutch fans but with my mounts and radiator forward it still does not have enough room to clear the clutch part of the fan on my 86 or 96.
Now on my 96 s10 I cut the front support as well and moved my radiator forward to clear a fan. I use a 7 blade flex fan with a 2 1/2 depth on both of my builds as I can't fit a clutch fan as it is tight in there with radiators as far forward as they go. With a stock one row radiator like the ones for the 4.3 v6 then you could fit a clutch fan but anything performance and like stated they will not keep a performance v8 cool in stop and go traffic. The radiators listed below is what I use on my 96s10 and the other one from summit I use on my86s10.
For my 96 s10 I use a shroud for a 96 s10 with the 4.3 v6. I had to customize it some but it allows the most air to be pulled through with my fans.
Another option is I have read for electric fans if you want to go that route then use a dual electric setup dodge intrepid from 98 to a few years after that and I have read they cool pretty well. For my 96 I ended up with a 180 oem stat and a 17 inch 7 blade flex fan and it runs about 190 all the time and sometimes can get a little hot in stop and go traffic but for most part it does very well.
I have not put the shroud on my 86s10 yet as I am also using the one from a 96 s10 to put on and try and cool it at idle but have not gotten around it yet to be able to comment on how well if it works good or not.
JEGS Performance Products 52000 JEGS Universal Performance Aluminum Radiators - Free Shipping on All Orders @ JEGS
http://www.summitracing.com/parts/gri-1-25271-x/overview/
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