puzzling pickup problem

[not2old]

I've always been able to smell antifreeze if a heater core has a leak and I don't have a good sniffer. I can usually smell it before it leaks enough to wet the carpet.

[Bird]

I've always been able to smell antifreeze if a heater core has a leak and I don't have a good sniffer. I can usually smell it before it leaks enough to wet the carpet.

Must be gettin' old. I forgot about that, but that was the first clue I had with one I had leak.

[boomer1025]

Take an have the cooling system vacuumed checked for leaks

[murphy1244]

Your windshield would be wet with defrost fan on if your heater core was leaking.

[randy41]

well i did smell it when i used the pickup wednesday but i decided the smell was from the guy driving in front of me. and maybe last saturday too. we'll see if the coolant level changes when i use the truck tomorrow.

[murphy1244]

Put your fan on high with heat and defrost. If the shield is wet its the core

[k0ua]

I'm not real sure on that model, but I think it would not drip to the ground. A slow enough leak can evaporate before it runs down and drips on the ground, and some heater cores (I suspect yours) will leak onto the floor/carpet inside the truck on the passenger side if the leak is big enough instead of outside. And of course at this point I guess we're not at all sure that's your problem.

Also with a leaking heater core, you will notice a faint anti-freeze smell and you will note "grease" on the inside of the windshield. When you try to wipe off the haze on the inside of the windshield, it will seem like smearing grease around.

James K0UA

[dave1949]

True, the exact problem is not known yet.

If the heater core is weeping and not isolated from the the inside of the cab, you should be able to faintly smell anti-freeze. Steamy windows from excess humidity is another sign. That may be masked at this time of year by air-conditioning drying out the interior air. It is noticeable in cool weather with the AC off.

Oops, I see I duped some replies I hadn't read yet.

[jomar215]

I've been reading a bit about not replacing the heater core and potentially using a filler of some sort to plug my slow leak. I've heard everything from black pepper to eggs, too. Anybody ever tried that?

And I sure can easily tell that it's the heater core - greasy inner windshield and ode de coolant - and it must be only a tiny leak that I can't find any wet spots for. But, if your heater core is leaking, you should know it easily.

[heviduty]

yesterday evening my wife and i were driving home with a load of fresh horse manure in the pickup truck when the oil temp light came on. well at first i thought the oil level was low so i pulled over and checked to be sure there was oil but now i realize that it is the oil temp light that came on. this is a 99 f-150 with the v6. so we continued driving and then i saw that the temperature gauge was on hot. pulled over again and shut it down and waited a couple. we started up again and it had cooled down a bit. so we got home without the truck exhibiting and of the symptoms you might look for in vehicle that is running way too hot. no burning smell. no coolant smell. no excessive blast of heat when i lifted the hood. when it cooled down i checked the radiator plastic tank and it was empty. i put water in. so now i finally got around to running it to try to get it to repeat the incident but it didn't happen.
do you think its possible that this occurred because of insufficient coolant? i will check the level again when it cools down a bit since i just ran it. must be a slow coolant leak somewhere?

If the plastic tank was empty the coolant level probably went below the thermostat. When it is that low the thermostat can't get a good sense of coolant temp until the coolant boils and blasts it with hot water. That is why it cooled down a little after the temp. spiked. I had a similar situation on a 95 F150 though it was a 5.0 v-8. The freeze plugs were leaking and I replaced the ones I could get to on the side of the block, but a couple on the rear of the block were partially covered by the bell housing. It didn't leak much, and I seldom used the truck, so I left the radiator cap loose, not off, just loose so the pressure wouldn't build up and blow the coolant out too fast. Anyhoo, I could tell it was time to add water when the temp would spike about 10 minutes after starting out, then settle back down. I'd guess you have a leak somewhere.