I have a flathead v8....the engine had a complete rebuild including being dipped and cleaned....new water pumps, new thermostats (either 160 or 180 not exactly sure), new radiator.
Here is the problem, I have driven it about 300 miles over the last two days... 60 miles at one time at highway speeds (55-60mph), the rest at varied speeds in town. The overflow reservoir keeps spitting out antifreeze??
The water temp has stayed below 180...normally 160-180, I have a gauge inside and a gauge on the radiator cap.
I picked the truck up two days ago, the previous owner said he had just filled the radiator....
I understand that the overflow could be from that, however I would have thought that by now it should be the correct level and no longer be puking.
Can anybody help??
Thanks in advance.

 

Is the cap the correct pressure rating?

 

I believe that it is, but am not sure....will that make a big difference?

 

Yes it will. What is the pressure rating on the cap you have now?
We need ta know this please.
But so will a combustion leak into the coolant system.
Such as a bad head gasket (not so common) or a crack somewhere (most common).

 

Should be a 4 psi cap.

I wonder if your PO filled it to the brim? You are supposed to leave about 1" below the bottom of the filler for expansion. If you have a recovery system, it will feed in water from the reservoir when it cools back down, then it will get pushed back to the reservoir when the engine heats up next time. With the immense cooling system capacity of these trucks (22 qts), your reservoir may just be too small for the amount of expansion. Most modern trucks have more like 10 qt. systems.

 

My radiator cap reads 16psi...Is that too high and will it cause my problem??

 

Does it fit your radiator neck, and seal properly? It is way too high a rating unless you have a replacement radiator that was made for higher pressure. Still not good for water pumps and gaskets.

 

Pretty common to to try and cure the overflow problem with a higher pressure cap . I would suggest a cooling system pressure test to try and locate or eliminate a cracked Block , Cyl. Head , blown Gasket etc. Just a thought.

 

X2 on getting your system checked as Allan suggested.

And please let us know what you find out. So many peeps
never do let us know. Than the next guy to Google this thread
never gets an answer.

Mike I just checked out your album. That is a beautiful
truck. From your post I get that you have only had the
truck a few days. Right? So the pic's in your Album
are from the OP ya got it from? Or did you put the engine
together?

 

I'm curious what is going on with your shift lever? It appears to be bent downwards? Or else the shifter rods are way out of adjustment. It shouldn't be that low in 1st/3rd, must be hitting your thighs?!

 

Ross....no the shifter isn't hitting my thighs....actually it is in a really comfortable position. I can rest my hand there when driving.

As far as my cooling problem....I did not build this truck, I bought it. really I don't know enough to build one and I certainly didn't have the time either so this worked out quite well for me.

My fear though is that when I bought it the PO gave me all his receipts, I added them up and it came to just over $35k....I bought the truck for $26k.
He seemed like a really nice man and convinced me of his honesty, but you know as well as me that crooks also seem honest.
With this problem I am worried that I bought a truck with a bad engine...don't really want to add more money, but don't want to have a problem down the road either.

I have PM'd several of you guys on here and you have been great in giving advice....it is awesome the help you give.

I plan on driving this truck and dependability is the most important factor for me.....ANY AND ALL advice is more than welcome.

I am going to go to Auto Zone in a few hours and get a new cap plus their tester and see what I end up with.

I want to drive this truck about 120 miles tomorrow morning....anything you can think of that I should look out for between now and then???????
Thanks a lot,
Mike

 

I wouldn't get too worked up on the spitting problem unless it is a constant thing. Very common for there to be air trapped in the system (like in the heater core) and to sit there until a good highway run. The important thing is, it is not running hot. If there were something really wrong, it wouldn't be running at normal temps.

Can you post a picture of your overflow / recovery canister?

 

Well I wanted to give an update... a lot of you guys have been really helpful and hopefully this will help someone else in the future...

I went to autozone and borrowed their radiator tester....the coolant system seems to check out ok...I had to move the truck out of my garage to get to some other tools for a friend so the engine was warmed up to about 140 before I was able to test the system. Put the tester on it, ran it up to 7psi and waited for about five minutes. The tester lost about a pound or so, and I figured that would be from the coolant cooling off???
The previous owner gave me another cap, I tested it, came out to be 4psi so I put it on the did a test drive this evening. The ambient temperature was about 85, I ran the truck through some tough paces no highway speeds though, but I did take a pretty steep and long hill, the temp didn't go over 180 as long as I was moving. When I slowed down in city traffic the temp went up to 200 though....that was the first time that happened so I am a bit concerned. After I got home I checked the reservoir then about an hour or so later checked again, for the first time it did pull about a half quart back out of the reservoir. But, the coolant level in the radiator was below the core???? Can any one tell me if that will be a problem down the road??

Ross I tried to get a picture of my reservoir but cant figure out how to do that on a thread...it is basically a round chrome cylinder that will hold about a quart.

 

Try this: With a cold/cool engine, fill it to within an inch of the top of the tank. Start it up with the cap off and let it warm up to 160 +/-. Water level should be getting close to the top of the top, if not add some water, and put on the cap. Fill the reservoir to about 75%. Drive it around, bring it home and let it cool. See if you have any repeats of the burping.

If your reservoir only holds a quart, I'd suspect it is too small.

PS -- note that pressure rating on the cap does not affect running temperature.

 

Good advice there!