Solved Radiator Overflow

[itzbinnice]

On my 95 XLT the radiator was replaced last year at a repair shop. I don't use the vehicle much. I have been noticing when I check the water level in the radiator when it's cold it seems to be low. I also noticed after I top it off, then use the vehicle for awhile, the water level in the overflow tank rises when the vehicle cools down and remains at that higher level.
I just wonder why if the radiator gets low it doesn't draw from the overflow tank.

The vehicle has no water leaks and oil level remains the same and has no water content. The heater works properly and no interior leaks. The water pump was changed several years ago and the vehicle does not overheat and i get good heat in the cabin.. I changed the radiator cap and it made no difference. I just checked it now and had to add a bit shy of a pint of 50\50 mix to top it off.

At first I thought it was a clogged hose from the overflow to the radiator, but that can't be it since the antifreeze is going from the radiator to the overflow tank.

Any suggestions on what can be the cause?

 

[my98nnj]

Check / change the radiator cap. Also make sure the hose that runs from the radiator cap neck is not cracked. The cap controls the pressure and vacuum which pushes and pulls fluid from the bottle as it expands and contracts. If the cap is faulty or the hose is cracked, it may push but not pull back from the tank.

 

[itzbinnice]

Check / change the radiator cap. Also make sure the hose that runs from the radiator cap neck is not cracked. The cap controls the pressure and vacuum which pushes and pulls fluid from the bottle as it expands and contracts. If the cap is faulty or the hose is cracked, it may push but not pull back from the tank.

As mentioned I've already replaced the radiator cap and the issue remained.
Thanks for the suggestion, I will check the hose but if it was cracked I would suspect it would shows signs of leaking which I don't see.
Perhaps its small crack and prevents keeping the pressure a constant.

 

[Runnin'OnEmpty]

Check where the hose connects to the radiator and
the expansion tank. If the hose loses vacuum the
system won't pull coolant back into the tank. A
couple of mini hose clamps on the hose ends might
help.

 

[Turdle]

Also, sludge can clog the nipple connector on the bottom of the reservoir tank. This will allow hot coolant under pressure to go in, but when the flow reverses the debris re clogs the bottom connection blocking flow back into the radiator.

Take the overflow hose off the radiator end, wipe it off with your shop rag, man up and blow on it.
( or you could use very low pressure from an air hose-but be careful to use very low pressure or coolant will go everywhere)

If it is clogged it will take some effort to make bubbles in the reservoir. Be sure to hold the hose end high or coolant may start flowing out.

If the reservoir is real dirty, use the overflow hose to drain it into a bucket under the truck, then use a shop vac to get all the crud out. If it doesn't drain out very quickly, then you have found the problem.

you might have to flush it with water--re vacuum a few times to get all of it out. Hope this helps.

 

[itzbinnice]

Thanks for the suggestions guys on clamping the hoses and cleaning out the expansion tank. I'll do that tomorrow and will test on Thanksgiving Day when I will be taking a trip. I plan on cutting the hose on each end about 1" just in case it is stretched and not making a good seal.

I'll report back after the Holiday and see if the problem is fixed.

 

[itzbinnice]

Update -Problem Solved
Turdle your suggestion was right on target, the hose was clogged as well as the expansion tank. I blew into the hose and couldn't get any bubbles.
I like doing it right the first time so I removed the entire expansion tank unit (includes washer tank). What i discovered were clear crystal like particles that blocked the expansion tank outlet. I also found those particles inside about 3 inches of hose that connected to the expansion tank.

Cleaned the tank thoroughly and snaked and rinsed the hose clean and now everything flows freely. I took it for a ride and reached operating temperature then let it cool. Radiator water lever was good and the expansion tank water level remained the same.

The only thing I can think of of how those crystal appeared was when the radiator first leaked last year, I believe I may have add some sort of stop leak (not sure). If I did, that did not correct the problem so I had a shop replace the radiator. I tried to unsuccessfully fix one thing but broke something else in the process.

 

[Turdle]

Cool. Glad it's back to normal again!