Volvo Overheating

[mj81]

I have an elderly Volvo MD5A, which is overheating, problem goes away once I remove thermostat, I have replaced thermostat but issue persists. I'm afrain that i have may have a restriction in the head, is there any product out there for clearing this?
What are the risks of running without a thermostat?

 

[Evadne]

I had a similar set of symptoms last year. Although I convinced myself that it was a blockage in the head or block, it actually turned out to be a restriction (100% blockage, actually) in the exhaust. There are products for clearing deposits out of engines, basically weak acids or alkalis, but it's easy to check the exhaust and waterlock first.

Look for descaling products e.g.
this one
or this kit

 

[VicS]

[ QUOTE ]
descaling products

[/ QUOTE ] Or Rydlyme marine descaler.

Or even Fernox DS-3 central heating boiler and water heater descaler from plumbers merchants or DIY stores.