Cooling system maintenance

[zchael6]

Hi there!

Ive recently acquired a 1998 940 celebration with AC. Its been regularly serviced but its overdue a cam belt change which im going to do. The other thing that i would like to pay some attention to is the cooling system. The radiator, hoses, expansion tank etc all look v old and in need of replacement. I was wondering whether anyone could help recommend a list of part numbers that could help me order replacements. At the moment im a bit confused about the number of variants. Mine is 4 speed auto.

Ive got the cam belt and tensioner its just the cooling system parts i could do with some help on

thanks!

[Ian21401]

Welcome to Volvo ownership and this excellent forum.
My car is a 1992 940 2.0L, without AC. I usually rely on my main dealer to supply the correct parts by providing him with the car’s VIN as this identifies exactly what is fitted to my particular car. I appreciate that your car may have subtle differences so would suggest quoting it’s VIN.
For what it is worth, these are the part numbers of the items fitted to my car:
Radiator Top Hose..VO3536130,
Radiator Bottom Hose...VO3514988,
Radiator to Expansion Bottle Hose...VO9155496,
Thermostat Kit (92 deg.) VO0273307.
In the past I’ve used mild steel hose clips, trying to obtain genuine “Jubilee” brand when possible, but I’ve recently found genuine “Jubilee” brand stainless steel hose clips on the internet. ( TRsalesUK fulfilled by Amazon, many sizes available.)The hose clips on my car have been on for several years so as and when I need to remove/replace them I will be using stainless steel.
Hope this helps.

[Forrest]

Also remember to pay attention to the oil cooler hoses:

9161383 & 9161384

And the heater hoses, which you will need to confirm are for a RHD car with AC.

In my experience these smaller hoses are the ones that are most likely to fail. I also agree with the comments about changing to stainless steel hose clips. I use JCS Hi-Grip Stainless Steel Hose Clips - Marine Grade. Check the number on your existing clips for the correct sizes.

Nearly every part of the cooling system should be regarded as a service item. Over the years I have had to replace thermostats, radiators, water pumps, heater matrix, heater valves and header tank. The latter will almost certainly need replacing if you disconnect any hoses from it, especially the one underneath.

[zchael6]

Thanks very much for the replies! Ok that’s really useful info. I have only had the car a few days and have noticed minor fluctuations in the amount of coolant in the expansion tank. Is there a way I can check the cooling system before I buy all the parts? I heard something about a leaky head gasket and fluctuations in the coolant level in the expansion tank.

[Ian21401]

There are others on this forum with more knowledge and expertise than I who will probably contribute. I believe that it is possible to pressure test the system for leaks and to test the coolant for contamination.
I also suggest renewing the heater hoses as a matter of course but make a note of which way they are connected as there have been instances of people connecting them the wrong way around. Suggest obtaining a new heater control valve to keep in stock as some of these valves are becoming unavailable.
When you do refill the system I strongly recommend using only genuine Volvo coolant diluted to a 50/50 mix.

[Laird Scooby]

Originally Posted by zchael6

Thanks very much for the replies! Ok that’s really useful info. I have only had the car a few days and have noticed minor fluctuations in the amount of coolant in the expansion tank. Is there a way I can check the cooling system before I buy all the parts? I heard something about a leaky head gasket and fluctuations in the coolant level in the expansion tank.

The level in the expansion tank will vary between cold and hot.

I was also going to mention JCS hose clips, Jubilee copied their design but not so well. If memory serves, HCS are stainless anyway and have a better worm-drive mechanism so are worth paying the extra for.

As for water pumps, it seems the current favourite replacement is SKF but if the existing one isn't leaking, it's probably the original, in which case, leave it be!

Worth mentioning the antifreeze - use ETHYLENE GLYCOL antifreeze NOT OAT! Also worth renewing the 'stat and reverse flushing the cooling system.

These are the instructions for reverse flushing the cooling system for best effect with minimal chance of any problems afterwards. I've typed them out many times and don't fancy doing it again so i've copy&pasted from last time i did it which was for someone on the 200 section so any references to a "B21 engine" should be read as B230/200 whichever you have.
It has worked for me for many years on many cars without a problem.

Before you start, douse the Jubilee clips involved and the 'stat housing nuts/bolts with releasing/penetrating oil. Let soak for a few days and repeat. Leave a few days more and give a final dousing.
Set the heater controls to "HOT"

Remove the bottom hose from the rad to drain the old coolant - catch it in something for safe disposal.

Refit the bottom hose and refill with plain water. Add a heavy-duty cooling system flush such as Comma X-Stream Flush or similar.

Take it for a drive. Instructions on the flush usually say "Run the engine for 15-20 minutes, drain and reverse flush" Drive about that amount of time out and then return.

Let the engine cool. Remove the 'stat housing and the thermostat. If memory serves correctly, the 'stat on the B21 has the seal around the actual 'stat, basically a grooved "O" ring. Clean the areas in the housing and on the head where the seal sits.
Refit the housing (no 'stat).

Remove the top hose from the rad. Insert your garden hose into the top hose and turn the hose on. Water should start flowing from the rad stub - go and have a coffee!

Come back after your coffee (remember it was clean water in there so not a problem about drains etc) and check to make sure the water is running clear. Move the hose into the expansion tank (can't remember if yours has one but if it does, do this step) and observe the water coming out of the top hose stub. Once clear, turn the hose off and remove the bottom hose from the rad to allow the majority of the clean water to drain. Refit the bottom hose.

Take the new 'stat and smear some silicone grease into the groove of the new seal, fit the seal around the 'stat so the 'stat sits in the internal groove. Smear the outside of the seal with silicone grease too. Remove the 'stat housing and fit the new 'stat, jiggle valve (if fitted) uppermost. Refit the housing and tighten the fasteners.

With the cooling system now intact (but empty) add about 4.5L of concentrated Etheylene Glycol antifreeze to the system.

I can't remember the total capacity, i think it's 9.6L on yours so you'll need 4.8L antifreeze if so, check the capacity and work out 50% of the total and put that amount of EG conc anrifreeze in.

Top up with water to the "MAX" level. Refit the cap and take it for a drive, return home, park preferably facing slightly uphill and leave to cool, overnight if possible.
Check the level the next morning and top up with water if necessary. Remember you've already added enough antifreeze, any shortfall in content needs water only.


This should be self-explanatory but any questions, feel fre to ask!

Oh yeah, welcome aboard the forum too!

[zchael6]

Wow thanks so much for the detailed reply! this is great info. Thanks again.

Yesterday i was changing the drivers side wing on the car because the original has a big dent in and i had to take the windscreen wipers off. When refitting, they no longer go. Have i tightened the nut too much? or not enough? I can hear the motor trying.

Thanks!

[Ian21401]

Did you only remove the wiper arms from the shafts? In which case I would remove the arms again and check whether the shafts are moving. If they are not moving then one or both may have seized due to age and lack of lubrication. Does the motor sound as if it is running freely or does it sound as if it is trying to run but cannot? First try some lubrication on them and give it time to seep in. If that doesn’t help you will probably need to remove the scuttle to access the motor and mechanism.

[Laird Scooby]

With the wipers, it's back to basics i'm afraid.

Remove the wiper arms again, wrap a loop of tape round the spindle so it leaves a tail like putting a luggage label on the handle of a suitcase and then switch the wipers on.

This way you will be able to see if the mechanism is operating.

Switch the wipers off and watch to ensure they return to the park position.

Refit the arms, one at a time, testing after fitting each arm. As you fit each arm, place the arm in the parked position and apply a bit of pressure to the arm a couple of inches from the spindle as you fit the nut. This helps to ensure the arm sits squarely on the spindle and the splines engage correctly. Tighten the nut with a spanner or socket but not over-tight.

Check the operation of the wiper arm by using the screenwash function so the blades aren't dragging over a dry screen.

Be ready to switch off via the key if for some reason you've misaligned the wiper arm.

Repeat for the other side.

[zchael6]

Thanks for the reply’s

The shafts are working when the wipers are off. Yes i removed them to put a new wing panel on the drivers side, I had to pull up the piece of panelling between the bonnet and the windscreen to get at on of the bolts on the old wing panel.

I think i put them back on badly/ left on right etc and have now possibly stripped the splines on the wiper arms as i started the wipers and the motors were going by the arms weren’t. The splines on the motor assembly seem ok, its just the splines on the wiper arms them selves. Looks like i might need to get new ones from a breaker!

Thanks again