Ongoing saga Volvo 850 overheating stalling under load
 

Volvo 850 GLS 2.5 petrol non turbo 1996 wagon

I live in a small island country with no Volvo dealer or any good vehicle maintenance really. three years ago it started stalling when warmed up and water would bubble up from the expansion tank, the water turned coffee colour. Oil is good, ATM oil is good. Water dripping from exhaust. We diagnosed head gasket and due to difficulties here, I left it 3 years. However, a good mechanic turned up and changed the head gasket, and it seemed the problem solved. Also changed fuel pump, cleaned filter, changed coil and spark plus, many of the senors including the water sensor. It had no faults logged detected by a code reader.

The mechanic thought the thermostat was not circulating water to the engine, so we removed it (it is a tropical country here) and blocked the by pass tube so the water always goes to the engine. We'll get a new thermostat later.

Situation is not fully resolved. Yesterday took it out for first ride to get tested (passed) but after about 6 km when fully warmed up, it started stalling under load again. What happens when in this state, it starts OK and the engine revs completely freely up to max in neutral. But when you put your foot down under load, i.e. to start moving, it stalls. On the flat you can get it going when in this state by just letting idle power move it and once going you can get some revs up. It only stalls under load. I struggled to get it home, stopping frequently and letting it cool down.

When cold I checked the water and it has lost 1.5L from that one drive. So it seems to be still overheating. The water is clear though and head gasket full kit was fitted.

Any thoughts welcomed! I really want my Volvo back....

Did you change the plug wires? It sounds typical of old wires that as soon as you put a load on the engine it stalls. Check for a date code, OEM Volvo wires will have one. If it`s more than 10 years change them. Use OEM Volvo Bouigard wires

thanks
 

Thanks, you are right problems with these old cars can be the result of several things together, I will change those HT cables. However, that doesn't explain the apparent over heating or cooling system symptoms such as the 1.5L water loss over a short trip. When cold right up to fully warmed up (3 oclock on the temp dial) it is absolutely fine and pulls as strong as ever. Its only after warming up the problem develops. If its the HT cables, could it be evident only when they are hot from the engine?

The HT cables wouldn`t have anything to do with your overheating issue. But it would make sense that when they get warm from the engine for them to cause your stalling under load issue if they appear to be old. Also humid air can only exacerbate a HT cable issue. If your losing water like that and there is nothing leaking externally than I hate to say it but it`s leaving through a head gasket issue out the exhaust.

We just changed the head gasket. I think the waters coming from the expansion tank, after over heating.

If it was sitting for 3 years and as old as it is then I would suspect a clogged up radiator

Yes I am thinking about that. Thanks for the discussion. When it did have a head gasket issue (the water turned coffee colour) it left a lot of deposits and that may have clogged the radiator despite the flushing that we did.

I am just wondering what unintended consequences might be of blocking the bypass tube. that is pretty nice design for getting the engine full of coolant. I would not have blocked that.

Yes me too! I think a new thermostat would help. The thing is, the parts are available only overseas (mail/shipping to here takes several weeks at least) , so it needs me to be sure about what I need, If I was living in Australian (nearest country with support) I could just get part X and try it. If it is not the one, then get another part. I have to take a 3 hour international flight to get access to the store that sells a $10 part. So thats how things are done here. It seems to be the cooling system for sure. Maybe a new radiator as well.

OK I have replaced the HT leads and expansion tank which had a crack, which was why the water was coming out. The cooling system is now fine and warms up to to a normal temp and stays there, fan comes on as required.

The engine is running noticeably better with the new HT leads, but once fully warmed up it still stumbles and stalls when trying to start under load or accelerate from slow speed. It runs perfectly and can start on a hill no problem UNTIL it is fully warmed up. Unlike before, it does tend to catch a bit better and keep going as long as you're rolling on the flat, but its still too bad to risk taking out on the open road. Another symptom is that it is idling very fast, over 1000. Sometimes the idle settles down even higher , say 1200 or so.

Until warmed up, it is 100% normal.

So it has a new coil, new HT leads and plugs, new sensors, no thermostat (we're in a tropical country), good cooling system, the head gasket changed.

Could timing belt mis fitted (i.e. by one rib) or ignition timing cause this?

Fuel system? Throttle plate issue? Dirty injectors? But why only when hot?

The ignition switch is also a bit loose, one has to edge the key back a teeny bit once started to ensure all the circuits activated (indicators, shift lock, etc). Could that cause this issue? I would have thought an electrical ECU issue would also affect cold running.

At a complete loss. Will now change the ignition switch and the rotor head. Nothing much else to change...

Would really appreciate any help. Thanks!

All sorted after new plugs, HT leads and a general TLC service. I have my lovely 850 classic back on the road. It was the head gasket and a cracked water expansion tank (a very small fracture) and generally neglected components that needed a good service.

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Nice. Did you have the head milled to true it up? Did you get new head bolts?

I like to complete a thread to let others know the final outcome.

It's very difficult here to get quality work done (small Pacific islands country). Most auto mechanics are individuals without proper workshops. So it was quite a job to get the 850 head gasket changed properly, but in the end it was done nicely. yes, a full new kit with head bolts etc but looks like no milling needed (wouldn't have been possible here). Then it was just a case of replacing overdue items over 20 years old such as HT leads, coil, fuel pump, vacuum tubes, that together were causing the misfiring and a good clean and tune up and it is now running beautifully. Still it's an old car and no-where much to drive it here, but I'm a fan of these great motors so its great to have it back after 3 years off the road. It will always be a "project" as bits keep falling off - but surprisingly, new parts are easier and cheaper to get than some Japanese models (from Aussie dealers).

New Caledonia, Fiji, Tasmania, New Zealand where is this small island???

New Zealand? Ho ho... no! That's a first world country....I and my 850 are in Solomon Islands. As far as I know it's the only Volvo on the road here