180 degrees but puking out half radiator

[trailblazr81]

My K20 with 383 is runnig cool about 180 degrees on the new Autometer Phantom gauge but it pukes out half the coolant in the radiator. Ive tried using a li'l catch can but it still gets everywhere and I need to refill the radiator. Im running a 16 pound cap but its a couple years old... Any ideas?

 

[nvrenuf]

Sounds like the cap to me, if not its cheap.

 

[danny7139]

Sounds like the cap. If I remember it is only like $10 at autozone.

 

[uglytruck]

Ditto on the cap. My boat (w/ a 305) was leaving coolant in the hull every time I took it out. New cap no coolant.

 

[jarheadk5]

Replace the cap.
Refill the radiator when it's cold.
Start the engine with the cap off, and continue filling until the radiator is full. If your upper radiator hose is a little higher than the rad cap, push down the high area to burp any trapped air out of it.
Should be OK...

 

[blazerpro79]

how much driving in does it take to overflow your radiator and about how hot is it outside?

i am gonna say cap too, and agree to rotate your hose if it is higher than the cap.

 

[trailblazr81]

It will start doing it after maybe driving from point a to point b in town...like 10 minutes. Its been getting warm here in Hollister in the 90's. But I also visited some friends closer to the coast where it was in the 70's but still had same problem.

 

[thfonz98]

cap....heck my brand new acdelco one from chevy was found to be bad when i had to take my radiator to my trusted radiator shop.

 

[dirtwarrior17]

Or it could be the radiator. If the cap doesn't seal completly to the radiator because of warped or bent radiator a new cap won't fix the problem.

 

[sweetk30]

if it still does it then possible exaust leak in to the system(head gasket/cracked head/cracked block) can get a tester from parts store like napa.

 

[trailblazr81]

I think I got it fixed. Bought a new cap for $7.99 and drove in town on on the highway for about a half hour. Temp was good and when I got home only a few drops in the catch can!! Bumped the timing from 10 to about 15 and is running better too!!!

 

[HarryH3]

Modern cooling systems are designed to push coolant out of the overflow tube. As the coolant gets hot it expands, so the cap lets some out, to flow to the coolant recovery bottle. When the engine cools down, a vacuum is created in the cooling system and the coolant contracts. A small valve in the radiator cap opens and the system sucks some of the coolant back from the recovery bottle. The system is designed to always keep the radiator full by moving coolant back and forth. If you don't run the recovery bottle, then coolant will be pushed out and the radiator will always be low by a couple of inches when the system is cool.

 

[trailblazr81]

Right I understand that. But it was filling the catch can and more!! Half the radiator and the intake manifold was dry!! But now its all good!!