Coolant overflow

[ab777]

Was driving my ‘65 Imperial today to put some more break in miles after rebuilding the engine and almost replacing everything. Put about a 100 miles on it today and all of it was highway driving, on the way back, after almost 90 miles of driving I started to smell a funny smell, so I decided to pull over in case.

I get off the highway and take a look underneath the hood and see coolant coming out of the overflow. Unfortunately my temperature gauge suddenly no longer works so I did not know how hot it was running.

I did have an infrared thermometer with me, and after checking the temps all over the engine and other components including the radiator nothing read more than 190f. There were absolutely no signs of overheating, and the radiator hoses were soft to the touch.

I drove the car about 5 miles to get home and got stick in a bit of traffic, but it did not end up doing that again, and I did not see any coolant coming out of the overflow again.

Does anyone know what might have caused this? Was it simply too much coolant? Or is it something else? Because for two hours on the highway there was absolutely nothing wrong with the car.

 

[Fury1969WI]

not sure how you filled your cooling system. For filling/burping those systems i really appreciate the Lisle kit; Advance Auto Parts - Down for Maintenance

In my opinion the system could have been a little over filled things heat up, expand, presto!

Otherwise a big ole air pocket might have purged and created an event.

What's your coolant level know? is it staying steady?

 

[ab777]

not sure how you filled your cooling system. For filling/burping those systems i really appreciate the Lisle kit; Advance Auto Parts - Down for Maintenance

In my opinion the system could have been a little over filled things heat up, expand, presto!

Otherwise a big ole air pocket might have purged and created an event.

What's your coolant level know? is it staying steady?

I’ll have to check and see where the coolant level is at right now, but I wasn’t the one that filled the cooling system, as I had the mechanic do that when I installed the new radiator after rebuilding the engine.

 

[SIPLOWGUY]

It may very well have been overfilled. You need to check it cold.

 

[ab777]

It may very well have been overfilled. You need to check it cold.

That’s the plan, because there were no other symptoms, no smoke from the exhaust or anything of that nature.

 

[CBODY67]

It was certainly a great day for a drive. It was up here in DFW.

190*F for the engine is not anywhere near "overheated" with a 180*F thermostat.

On the round-top radiators, the "Full Cold" coolant level should be about 1 inch below the bottom of the filler neck. Maybe up to 1.5" or so? Check the Chrysler factory service manual for verification.

Sounds like the system hit its "over-full" level and made a mid-course adjustment. I would hope that was all it was!

Keep us posted, please.

CBODY67

 

[ab777]

It was certainly a great day for a drive. It was up here in DFW.

190*F for the engine is not anywhere near "overheated" with a 180*F thermostat.

On the round-top radiators, the "Full Cold" coolant level should be about 1 inch below the bottom of the filler neck. Maybe up to 1.5" or so? Check the Chrysler factory service manual for verification.

Sounds like the system hit its "over-full" level and made a mid-course adjustment. I would hope that was all it was!

Keep us posted, please.

CBODY67

That’s what I am hoping too, I am thinking of checking the coolant level while it’s cold and then take it out for a drive to see what it does.

 

[edbods]

almost replacing everything

Was the radiator replaced? If not it might be clogged. Mine will heat up on the highway and puke coolant. On surface streets it's fine, still bubbles a bit of coolant but not as much. But I've still got the factory radiator and I strongly suspect it's clogged as someone else mentioned getting their rad recored, and never having an overheating issue ever again. Try a reverse flush with water only then refill with demin and antifreeze and go for a run again

 

[carguy300]

Sounds like overfilled. Both my 68 300's did the same thing after filling than driving a decent distance. After they cooled down the level was just below the neck and it has never happened after that. Hot light never came on either.

 

[GOLDMYN]

make sure the radiator cap is good, cheap things first

 

[ab777]

Was the radiator replaced? If not it might be clogged. Mine will heat up on the highway and puke coolant. On surface streets it's fine, still bubbles a bit of coolant but not as much. But I've still got the factory radiator and I strongly suspect it's clogged as someone else mentioned getting their rad recored, and never having an overheating issue ever again. Try a reverse flush with water only then refill with demin and antifreeze and go for a run agai

Was the radiator replaced? If not it might be clogged. Mine will heat up on the highway and puke coolant. On surface streets it's fine, still bubbles a bit of coolant but not as much. But I've still got the factory radiator and I strongly suspect it's clogged as someone else mentioned getting their rad recored, and never having an overheating issue ever again. Try a reverse flush with water only then refill with demin and antifreeze and go for a run again

Yes it was replaced with a “new” nos one. My old one had been leaking and was corroded when I bought the car.

 

[ab777]

Sounds like overfilled. Both my 68 300's did the same thing after filling than driving a decent distance. After they cooled down the level was just below the neck and it has never happened after that. Hot light never came on either.

That’s what I am thinking it was, I did drive it a few times after the coolant was added, but they weren’t as long as my last drive where this happened. So I am hoping it’s just getting rid of the excess coolant, the only weird thing was that there was a weird smell.