Puking Coolant

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Jul 19, 2023 | 08:44 PM

ChrisMelton78

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Mountain Pass

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Puking Coolant

OK. As per usual, nothing is ever simple. Bought this 1986 F150 with the in-line v6. Owner said it was running hot on him. So, first thing I did when I got it was replace the thermostat, thermostat housing (I broke the ear off the original one), and a new water temperature sensor. Got everything reinstalled. Filled it up with coolant with the engine off. Then started the engine (with the radiator cap off) to let the coolant circulate and work the air out. The level would go up and down, up and down until suddenly when the truck warmed up it started puking coolant out of the radiator.

I expected to see the water level go up and down, but I have no clue why it just suddenly started puking coolant once it warmed up. Any thoughts?

Jul 19, 2023 | 09:00 PM

kr98664

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Joined: Nov 2013

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Quote:

Originally Posted by ChrisMelton78

I have no clue why it just suddenly started puking coolant once it warmed up. Any thoughts?

Yeah, it's cuz you were running the engine with the radiator cap removed. Probably just an air bubble or two working their way out of the system. It's not really any sort of fault. With the cap on, you'd have never noticed.

I'd fill the system to the normal level. Install the cap. Drive around a bit. Check the level every morning and top off as needed. After a few days the level should stabilize.

Jul 19, 2023 | 09:22 PM

ChrisMelton78

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Mountain Pass

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Cool! That's pretty relieving. This ol rascal has been giving me fits since I bought it, but has a lot of potential. Just working out all of the kinks. Thanks again for the info!

Jul 19, 2023 | 09:31 PM

BigBlue2

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Quote:

Originally Posted by ChrisMelton78

Cool! That's pretty relieving. This ol rascal has been giving me fits since I bought it, but has a lot of potential. Just working out all of the kinks. Thanks again for the info!

Do you have an overflow bottle? I find that if there is air in the cooling system it works it's way out through the overflow bottle and then sucks in coolant to replace the air. The overflow system requires the cap be in place.

Jul 19, 2023 | 09:46 PM

ChrisMelton78

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Mountain Pass

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It does. I'll keep that in mind. Just let it ride and keep an eye on the coolant level. Thanks!

Jul 20, 2023 | 06:51 AM

Olds64

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Joined: Jun 2017

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From: Edmond, OK

Quote:

Originally Posted by ChrisMelton78

OK. As per usual, nothing is ever simple. Bought this 1986 F150 with the in-line v6.

Does your truck have the 4.9l I6? If so, once you get the wrinkles ironed out it will run pretty much forever.

Jul 20, 2023 | 08:13 AM

ChrisMelton78

Thread Starter

Mountain Pass

Joined: Sep 2012

Posts: 219

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It does!! That's really the main reason I bought this truck. I knew it had some issues, but at it's core it would be a good truck. Like you said, just getting some of the wrinkles out. Murphy's Law has been kicking me in the ***** lately thought. Haha!!

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Jul 20, 2023 | 09:18 PM

BigBlue2

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Quote:

Originally Posted by ChrisMelton78

It does. I'll keep that in mind. Just let it ride and keep an eye on the coolant level. Thanks!

When ever I change my coolant I also drain the overflow reservoir. Then when refilling I fill the reservoir half full and top off the radiator. I use a sharpie to mark the half full level. Get it up to operating temperature and then let it cool. Check if the bottle level went down. When cool check and top off the radiator again. You can remark the level on the reservoir or just note the new level relative to the old mark. Eventually it balances. Some have a hot fill mark at about 3/4 full. As long as you have it about half full you'll be good. I don't top off my reservoir when hot to the hot mark. Having room in the bottle is nice and having about a gallon of coolant in there will keep you topped off when there's demand.

Like every system check and monitor often.