240 Diesel overheating with ice-cold radiator part II

Thanks all of you for the answers, and suggestions!
Today I finally got good weather and had a deep look in the car, I
flushed the radiator. Actually took out, and washed it from the inside
and out, got some dirt out, but not much.
It is not in a great shape from the outside but it was not blocked.
Checked the new thermostat, it does open.
The tubes are in good condition, they don't flatten.
Put back everything and refilled the whole stuff trying to take the air
bubbles out by letting the engine run with the overflow tank open.
I did get some air out, but after the engine started to overheat again
(approx 10 minutes) and I had 2 liters of antifreeze which could not go
back in, because the tank was at max.

I did not take out the water pump as some of you suggestd because I
don't know how to do it and I don't have a manual (although I did find
one finally on internet from Bentley publishing,wich includes the
diesel modell but it would take 5 weeks to ship,)
Does someone know any other alternative or an internet site wich would
explain the changing of the water-pump on a diesel modell?

Also, what came to my mind is that the car had this problem directly
after I have had the plugs replaced (sorry I don't know the correct
name in english, the stuff wich heats up the engine for the diesel
ignition).
Could the changement of the plugs in any way affect the cooling system?
They were changed by a Volvo repair shop, but it's the first time I
took the car there so I don't know if they are really honest or not.

Thank you for your time
Andrea

 

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.

point up.

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?


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