Cooling system flush

[Macsea]

I have a pair of TMD40A volvos and one of them overheats when running above 3000rpm, what is the easiest way to flush the cooling system(is there an easy way) what de-scaler products would you recomend? also what other things should I look at with this problem.
Regards.

[ranger58sb]

I've used Rydlyme and Barnacle Buster, both effective.

One way is to inject solution via the engine's water pump">raw water pump. Fill the raw water path (oil cooler, transmission cooler, aftercooler, heat exchangers, whatever...) and then let it sit, flush later. Follow solution directions for duration.

Another way is to work out a recirculation path, in likely near the raw water pump (probably with impeller removed) and out somewhere after the heat exchanger, all driven by a small transfer pump. Not familiar with your engine, so can't advise better than that. Best to get useful fittings for connection at each end, bucket for outfllow (so sediment can separate), and so forth.

If you have dripless shaft seals, you'll have to plug those or pinch the hoses, otherwise you'll lose solution during circulation.

I eventually worked out a path so I can inject solution "backwards" to fill the whole system without having to remove the water pump impeller or pinch off our shaft seals... and using the fill/sit/flush worked that way well enough.

Be aware that heat exchangers can get plugged up enough so that a simple flush won't really get it done... and aftercoolers often need service to both raw water side and air side, so on-frame flushing doesn't mean you can bypass manufacturer's recommendations for service.

-Chris

[kinggeordie]

Seems these engines may be fitted with a thermostat, remove and place in boiling water the spring should open, if not a new one is needed, most people I know have just removed these completely, I have replaced mine as the engine works better when the coolant gets up to working tempature