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Chasing down cooling system 'demons'

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Butch

Chasing down cooling system 'demons'

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.

Gary Lewis

Re: Chasing down cooling system 'demons'

Administrator

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.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

ArdWrknTrk

Re: Chasing down cooling system 'demons'

Administrator

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.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Chasing down cooling system 'demons'

Administrator

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.

Gary, AKA "Gary fellow": Profile

Butch

Re: Chasing down cooling system 'demons'

In reply to this post by ArdWrknTrk

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?

Butch

Re: Chasing down cooling system 'demons'

In reply to this post by Gary Lewis

Will do leakdown test tomorrow

Gary Lewis

Re: Chasing down cooling system 'demons'

Administrator

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.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Chasing down cooling system 'demons'

Administrator

In reply to this post by Butch

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.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

grumpin

Re: Chasing down cooling system 'demons'

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.

Dane
1986 F250HD SC XLT Lariat 4x4 460 C6-Sold
1992 Bronco XLT 4x4 351W E4OD
1998 GMC Sierra SLE K1500 350 4L60E
Arizona

ArdWrknTrk

Re: Chasing down cooling system 'demons'

Administrator

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.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Butch

Re: Chasing down cooling system 'demons'

In reply to this post by grumpin

Radiator is new also, although it is a std. replacement from local auto parts store. Admittedly I am stumped, been fooling with things mechanical for nearly 67 years now.

Gary Lewis

Re: Chasing down cooling system 'demons'

Administrator

Well, I don't think I started wrenching any earlier than 5, so I've been doing it for 67 years as well. Hang in there, I think your leak-down test may tell you something.

Gary, AKA "Gary fellow": Profile

grumpin

Re: Chasing down cooling system 'demons'

Internal timing?

Dane
1986 F250HD SC XLT Lariat 4x4 460 C6-Sold
1992 Bronco XLT 4x4 351W E4OD
1998 GMC Sierra SLE K1500 350 4L60E
Arizona

Butch

Re: Chasing down cooling system 'demons'

In reply to this post by Gary Lewis

Have not done a leakdown test yet, was going to do a shade tree leakdown test, (cylinder at tdc, pressurize cylinder, listen at carb and tailpipe for intake or exhaust valve leak, and look for bubbles in coolant). But while doing a visual inspection of coolant while burping system (replaced thermostat), after it had run and big bubbles had came out there appeared to be a continuous faint stream of very fine bubbles in coolant. Decided we need to get an actual leak down tester with the gauges to get an actual measured percentage in each cylinder. Beginning to suspect it could be a warranty issue with the engine, but want to check all other options first. Engine sounds smooth absolutely no misfiring at idle, great throttle response, but this cooling hiccup is setting off the progress. Oh well, I always had a love/hate/love of old Ford trucks, still got my first a '64 styleside restin and rustin on the back fence line, ''I gonna fix it one day...'' can remember many a day 40+ years ago keeping it running on a near zero budget, depending on it as a daily driver, and it aptly filling that need, albeit smoky, drafty and rattily. Ah good times, wouldn't take anything for the memories, but sure glad I don't have to do the getting the forty (usually +) grind anymore.

Gary Lewis

Re: Chasing down cooling system 'demons'

Administrator

I think your shade tree test has shown up the problem. So while a true leak-down test might be warranted, that will just reduce the amount of air coming through the cooling system. However, you will then have true #'s to show the rebuilder. On the other hand, differences in cylinder-to-cylinder ring and valve sealing may mask the problem.

Good luck!

Gary, AKA "Gary fellow": Profile