[studrink]

I have a Chemspec 494, which recently overheated. ( by pass valve working fine) I found that the engine water pump was leaking. This was replaced, but the unit still overheated yet the radiator was cold. The thermostat was changed and all hoses etc were checked for water flow/air locks. Next time I used it it seemed fine and the radiator got warm. next day I had the same overheating problem, radiator cold again and now the solution from the wand is cold, despite the engine getting very hot. I'm running out of answers. Ive been using truckmounts for over 15 years so know all the usual obvious causes. Anyone had similar problems?

[michael fitzgerald]

the water in the radiator is designed to enter the engine, to stop the engine from getting to hot.
as you can imagine if you have water in the engine when its running  its going to get very very hot, thats why you have a radiator fan to cool the water temperature  down and stop it from over heating..
If you radiator is cold ? Then you need to check

1/ that the rad has water in it
2/ that the rad is not blocked, i.e. water not leaving it & entering the engine ( most likely ), remove all the hoses and check.

When you refill the system you must use anti freeze, this with stop any gunk build up in the radiator.
Hope that helps

[studrink]

Thanks for the input, but I've already had the radiator flushed and all hoses checked.

[michael fitzgerald]

if the radiator is cold then you must have a blockage somewhere?
you can't have water in a running engine and it not get hot,
check that the coolant is entering & exiting the heat exchanger,

[Simon@arenaclean]

Water pump seized, not circualting water. If the rad water is cold it cant be circulating so could even be a blockage in the engine block water ways or the rad core. There used to be a flushing agent/cleaner I used when I had a 1957 standard 10 which suffered from the same problem but can't remember what it was called. sorry.

[tony harrison]

Could be an airlock.

[Jim_77]

Simple logic - engine heat created in block... heat removed at radiator... cold rad = no heat being brought to it from the block!!!

A few months back I had to get my engine coolant h/x out for repair.  I could not believe the gunk and shyte that had built up in the bottom of the exchanger tank and the machine only had about 1,000 hours on it.  Sucked and washed it all out with my portable.

I put an open-ended hose off my outside tap into the top of the TM radiator and used my portable on the inlet to the h/x to flush the whole system out with loads of fresh water... it got an unbelievable further amount of gunk out from the rest of the system

Air lock obviously a possibility but I'd like to bet it's gunked up and stopped flowing through the block

[studrink]

Thats not a bad call Jim, I might try bypassing everything relating to the Truckmount side and connect all radiator hoses through the engine only and see if i get water flowing then.

[michael fitzgerald]

Did you sort out this problem ?