I think I have a blown head gasket, but I haven't been able to verify it. I borrowed one of those combustion leak test kits that you stick in the radiator and the fluid is supposed to change color if there's any exhaust gas, but it didn't do anything. Truck is an '89 F350 with the 460. Here's what I've got going on:

-It overheats. Up until recently, the gauge would be pretty much rock steady on the O in Normal. Lately, it hangs out around the A, and bounces around. The other day I was cruising down the highway, and within the span of a minute or so, it went from the A, to the red line and back twice. Every time I tried getting off the throttle, it would drop, but as soon as I touched it, it would climb right back up. Before this, it would cycle regularly, swinging throughout the range of the gauge.

-After running it and it gets up to temperature, if I go to restart it, it hangs, like there's something preventing the motor from spinning. Pretty much every time. I was testing a few things the other day and ran it without the radiator cap for a while, it got up to temp and I shut it off and restarted it a handful of times and it never once did it. My current guess is that there's a leak in the head gasket, and when I shut it off, the coolant system pressure forces coolant into the cylinder and when I try to start it, it hydrolocks a bit.

-I'm losing coolant. I don't drive it much anymore, but I filled up the radiator and the reservoir maybe two months ago and when I checked it yesterday, the reservoir was empty, and the fluid was low in the radiator. There also seemed to be a kind of film on the surface of the coolant.

-I'm pretty sure I'm losing oil, somewhere. Last time I changed the oil, I drained out 2 quarts. It should have been 6.

-When I was testing, just about every time I squeezed the upper radiator hose, bubbles would come up.


There's a few symptoms of a busted head gasket, that I haven't seen yet that causes doubt. There's no yellow sludge under the oil cap. When I drained the oil, it wasn't milky or looked like it had water in it. It does have the white smoke when I start it, but its been cold, so I'm not sure if that's just because it's cold or if it's coolant. And I could have swore there was a blue tint to the smoke, but that may have been my imagination.

Is there any other way I can test this and confirm it?

 

You appear not to have water mixed in the oil-that's good. You genuinely seem to be overheating, though....2 quick things come to mind: 1st is check that fan clutch....it can be VERY deceiving when they go bad. 2nd is it sounds like you have air in your cooling system, that must be purged until no more air bubbles out. Start with those and go from there....please kept us all posted & good luck!

Roger

 

Steam disappears right away, coolant smoke lingers and blows around, and will have a real acrid smell.

The coolant certainly sounds like it's being burned and if there's no evidence of a leak it can't realistically be anything else.

 

If the tester said no exhaust in the coolant then I wouldn't think it's a blown gasket. I read one time a guy put a clear mason jar under the exhaust tip right when starting to capture the moisture that drips out when it's starts to warm up and see if there is anything but clear water in it. Don't know how well that would work but you might try it and see if anything comes of it. Btw I'm no mechanic but using oil wouldn't mean a head gasket leak I wouldn't think but loosing coolant might. I'd check everywhere for leaks first. With nothing on the dipstick or under the cap and the test being negative it doesn't really sound like a blown head gasket. Also as far as a film in the coolant that could easily be your radiator lines leaking transmission fluid in the lines that run through the radiator. Mine was (wasn't sure that's what it was but per a mechanic get a new radiator and it should fix it) so I did and I'm pretty sure it stopped. If your radiator is old I'd replace that. It could have a pin hole leak and I think I only paid like $80 for mine. Good luck with the fix

 

Couple things, check your engine oil more often. Low engine oil level can cause overheating and significant engine damage. Low coolant regardless of the cause is a likely cause of your overheating. I would keep the engine oil level near full, and top off the radiator and then fill the coolant recovery system to the appropriate level. On older vehicles I like to use a can of bars leaks and a can of water wetter in a 50/50 antifreeze mix. Use the Bars-Leaks liquid not the pellets. A simple radiator flush and change of antifreeze along with a new thermostat and the two additives I mentioned may very well solve your overheating issue. Like the other poster says check the fan. Running the engine in an overheat condition hoping the temp will go down is wishful thinking and risky. IMHO!

 

A lot of good suggestions here. You may also try pressure testing the cooling system. That is usually where I start when I'm using coolant, and there are no smoking guns. You can rent or borrow a tester from the local auto parts store.


If you really think its a head gasket, I would pull the plugs when you pressure test the cooling system. If the pressure falls off and you have no visible external leaks, you may have a leaking head gasket, or a crack of some kind in a water jacket. At any rate, turn the engine over before putting the plugs back in, and see if any coolant comes out the plug holes. You don't want to risk a hydrolock. If the system pressure tests fine, the loss of coolant may simply be because of overheating. At that time you could try diagnosing the fan clutch/ thermostat, etc.


How many miles are on the truck? The oil consumption issue may be something unrelated. As suggested, check it more often, and see how quickly it is using oil.

 

I agree with the pressure test idea. I always start with a pressure test when trying to determine where I'm losing coolant at, on any vehicle. Bring it up to the pressure listed on your radiator cap, and see if it holds there. If it doesn't it means it's getting out somewhere.

I also agree with the engine oil level. if you were burning that fast, you would probably notice it. If it was leaking or mixing with coolant, again, I think you would notice it.

 

My experience with blown head gaskets have been, overheating coupled with oil/water mix (always) water being expelled at the tailpipe, and/or bubbles in the radiator. Overheating issues I've had (not related to head gaskets) have been, fan clutch, bad T-stat, collapsed lower radiator hose, timing issues, badly blocked radiator, and air in the system.
Might any of these apply here?

 

I was going through the exact problem on my '92 5.0. Changed the radiator cap. Fixed it, original was a 13lb which was probably working at 5lb or less. One downside, a new cap holding the right pressure, you run a good chance of finding leaks. I was going to run a 7lb cap which from what I've researched really isn't a problem.

 

This is the first thing I do to check for a blown head gasket. Most auto parts stores will rent you a leak-down tester.