240 Diesel overheating with ice-cold radiator part II

I can't think of anything related to changing the glow plugs that would mess up the cooling system. Can you squeeze the hose with the engine running to tell if coolant is flowing?

Does the interior heater work properly? If yes the waterpump should be OK. Make sure the thermostat isn't installed upside down, arrow should point up.

If you've never changed a timing belt before, this probably isn't a good engine to learn

Does the engine start properly and runs the same? If not they might have removed the injectionpump and put it back wrong and messed up the timing.

Do you have a lot of white smoke, either during startup or by the time the thing starts overheating?

IS the radiator cool all over or is there a single row at the bottom which is hot?

Engine is the same as in the VW LT van, and I suspect audi 5 cyl diesels could be similar

Frankly I couldn't eighter, but then again i don't know much about diesel engines so I asked. I did sqeese the upper hose coming from the engine, first there were some burps of air, then it got silent. I don't know if water is flowing or not, but it's quite "soft" and very easy to squeeze (a bit too easy I would say)

Does the hose get hot? I suppose not if the radiator is cold.

I once had an intermittent cooling problem with my gasoline 240, turns out what happened is a small pebble got in the radiator I picked up from a junkyard and then found its way into the water pump where it would jam up the impeller and cause it to just sit stationary while the shaft continued to spin.

The top hose gets hot close to the engine but the radiator end of the hose is cold.

I checked it today, it took about 7 minutes to reach normal temperature and then all of a sudden the needle started to climb quite fast. For my surprise the interior heating is not working this time ( it did before, although usually it takes some time before it starts to heat, I would say 10-15 minutes of driving with the winter) but this time I did not dare to let the engine run so long because of the overheating.

My dad warned me, so I did extra care to put back the thermostat the way it was there before, the springy part pointing towards the engine and the other end upwards (it wouldn't go in any other way anyhow).

I suppose you are right, I'm more familiar with taking apart and repairing notebooks than cars.

The engine starts very easily and runs well, some blue smoke at the beginning but it's 21 years old. There's no water in the exhaust if that's what you mean by white smoke.

It is cool all over from top to bottom. As well as the bottom hose coming from it, to the thermostate.

I called the Volvo service, who installed the glow plugs to see what he suggest. He thought it was still the problem of thermostate. He suggested to take it out and drive without, saying that with the winter it would be OK. I was quite surprised with the answer because I always heard that running the engine colder than the normal is really not good for it. In any case there's no way I could drive back the car to the repair shop in this state, it's simpl too far away.

My thought is that your water pump is bad, either that or something is lodged in the system. You could try removing the thermostat temporarily and see if coolant starts flowing but if that doesn't fix it, pull the water pump and check the impeller, it may be broken or jammed.

Running too cold is way better than running too hot, and it would determine the thermostat's part in the problem with certainty. Take it out and see. If your engine still runs hot you can be pretty sure that the water pump is the problem; if it runs cold then replace the thermostat.

Your mechanic is very strange. Winter is the time you need the thermostat the most, or your engine will never get warm enough to run efficiently.

Never underestimate a Volvo repairshop's capacity for evil.

bullshark

If you remove the thermostat coolant can go either through the bypass or through the radiator, which depending on the restriction in the radiator doesn't give much cooling. Is the bottomvalve on the thermostat present? Stick a gardenhose in the bottomhose. Can you get water through both the bypass (hole central underneath the thermostat) and through the engineblock? If you reverse the hose (stick it in the thermostathousing) do you get a free flow from the bottomhose? If you run the engine for a few seconds (coolantsystem complete and filled with water but with the thermostathousing removed) can you observe coolantflow?