Butch Posted October 3, 2019 Share Posted October 3, 2019 Could use some guidance on cooling system on 351w. It's a 1985 F150 has a new reman. Jasper engine. with Edelbrock performer manifold and carb. with MSD distributor and ignition. otherwise stock 351w 4v. specs. Also has Derale dual fan system and Tuff Stuff 140 amp alt. All new belts,hoses and water pump and currently has a 160 thermostat, have a 180 thermostat that we took out. The truck sat and idled for about ten minutes at the house and never got above 160 (factory gauge and aftermarket water temp gauge) with the fans cycling on as needed. But on road test truck temp climbed to over 200! This has happened twice and frankly I am stumped, and son is frustrated. Any light anyone can shed on this dilemma would be greatly appreciated. Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 3, 2019 Share Posted October 3, 2019 You might have a head gasket problem. I had a blown head gasket and the truck was happy below 45 MPH. But above that it overheated. Or, you may have the head gaskets in backwards. There's a tab that shows which way they are supposed to go, and if in wrong it'll overheat. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 3, 2019 Share Posted October 3, 2019 You might have a head gasket problem. I had a blown head gasket and the truck was happy below 45 MPH. But above that it overheated. Or, you may have the head gaskets in backwards. There's a tab that shows which way they are supposed to go, and if in wrong it'll overheat. 100% agree with the head gasket backwards, or one in upside down. Nice wheels! Please consider using the proper (195*) thermostat. It really helps engine longevity when the water gets cooked out of the oil. Sludging and acid are decreased, and all the internal components are clearanced for that operating temperature. Bearings and Pistons work much better when they actually fit within spec. Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 3, 2019 Share Posted October 3, 2019 100% agree with the head gasket backwards, or one in upside down. Nice wheels! Please consider using the proper (195*) thermostat. It really helps engine longevity when the water gets cooked out of the oil. Sludging and acid are decreased, and all the internal components are clearanced for that operating temperature. Bearings and Pistons work much better when they actually fit within spec. I know I keep saying this, but a leak-down test would reveal the problem if it is a gasket problem. You put air into the cylinders, one at a time, and if there's a gasket leaking you'll see bubbles in the radiator. Link to comment Share on other sites More sharing options...
Butch Posted October 3, 2019 Author Share Posted October 3, 2019 100% agree with the head gasket backwards, or one in upside down. Nice wheels! Please consider using the proper (195*) thermostat. It really helps engine longevity when the water gets cooked out of the oil. Sludging and acid are decreased, and all the internal components are clearanced for that operating temperature. Bearings and Pistons work much better when they actually fit within spec. This is a long block engine from Jasper , heads are as received (never removed) so should be a warranty issue. Any way to check without this removing heads? Link to comment Share on other sites More sharing options...
Butch Posted October 3, 2019 Author Share Posted October 3, 2019 I know I keep saying this, but a leak-down test would reveal the problem if it is a gasket problem. You put air into the cylinders, one at a time, and if there's a gasket leaking you'll see bubbles in the radiator. Will do leakdown test tomorrow Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 3, 2019 Share Posted October 3, 2019 Will do leakdown test tomorrow Head could be cracked. It'll do the same thing. And when you do the leakdown test, have all of the plugs out. Then check adjacent cylinders to the one you are testing as it is possible the leak will go to one of them. I had one that didn't open up to the cooling system until it got hot. But it went into the adjacent cylinder all the time, and showed up in the leakdown test. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 3, 2019 Share Posted October 3, 2019 This is a long block engine from Jasper , heads are as received (never removed) so should be a warranty issue. Any way to check without this removing heads? I don't know any way of checking without visual inspection, unless you can see a bit of the head gasket peeking out, like the tabs Gary mentioned. A coolant system pressure test should show a head gasket leak, but if there is a cracked cylinder that got past inspection (fits your symptoms exactly) it may not show up as water in the sump, because the crack is closed when cold. And a leakdown is done at tdc. Link to comment Share on other sites More sharing options...
grumpin Posted October 4, 2019 Share Posted October 4, 2019 I don't know any way of checking without visual inspection, unless you can see a bit of the head gasket peeking out, like the tabs Gary mentioned. A coolant system pressure test should show a head gasket leak, but if there is a cracked cylinder that got past inspection (fits your symptoms exactly) it may not show up as water in the sump, because the crack is closed when cold. And a leakdown is done at tdc. Could be the radiator. I saw new belts and hoses in your post, but not the radiator. I’ve had radiators do what you’re describing. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 4, 2019 Share Posted October 4, 2019 Could be the radiator. I saw new belts and hoses in your post, but not the radiator. I’ve had radiators do what you’re describing. That's a possibility Dane. I usually check for blockage by dumping a bucket of water through using a tractor funnel. If it pours out the bottom as fast as I can pour it in I consider it good. If you want to get fancy you could run it and check with an infrared thermometer in various spots. With his fan setup I can't imagine it not getting enough air. Do we know the sender is reading accurately? That IR thermometer pointed at a piece of masking tape on the water neck will tell the tale. (masking tape to eliminate any question of reflections) On Edit: two temp gauges so I doubt a bad reading. Sorry for not reading more thoroughly. Link to comment Share on other sites More sharing options...
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