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My 1994 Volvo 940T wagon with 176k miles questions re replacing head gasket.

940T Wagon 1993 & 1994

940T Wagon 1993 & 1994

Member
Joined
May 13, 2026
About 10 months ago driving my 1994 Volvo 940 Turbo wagon (that I have owned since new) overheated when I pulled off the highway.
The car slowed on a local road engine stopped running. I opend the hood steam was comming from radiator which was 31 years old original radiator. The electric cooling fan did not come on and I could hear the cylinder head gasket break and engine started rattling and shaking as coolant got into the engine. I think the car got low on coolant due to leaking radiator and the cooling fan ground or relay or fan motor was bad.
Also thoughts re putting a Swedish do88 radiator in that for a manual trans only...what kind of seperate radiator do I install and location to cool the trans fluid?

The engine prior to this always ran strong with no problems and original turbo. I am wondering if I can pull the intake/exaust manifolds/head off..check the block and head are not warped, look at condition of cylinder walls then replace all seals, timing belt and tensioner, water pump, get new radiator and hoses, have just the cylynder head rebuilt but NOT remove engine or rebuild rods, pistons?

Would also replace coolant pump, coolant fan, relay and ground.

Is this a good idea, just a head rebuild saving full rebuild for the future or a foolish idea?

What is keeping me from full rebuild is I dont have an engine hoist, or engine stand and ability to pull the engiine and the additional cost.
 
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Also thoughts re putting a Swedish do88 radiator in that for a manual trans only...what kind of seperate radiator do I install and location to cool the trans fluid?
 
There's no reason to replace the fan, or "upgrade" to an expensive radiator. I haven't killed a block from overheating but I have warped heads. I like to "field test" heads by removing the cam and lifters, then setting the cam back in and seeing how much it rocks on the center cam bearing. Anything more than "I can just barely feel it rock" I would be looking for a straighter head.

Head gaskets are a quick remove and replace job, the factory service manual says you don't need to replace the head bolts and how much warpage is allowed.

It's likely that there is a step/ridge worn into your bores. I wouldn't look farther than you have to, just get the car back up and running again.
 
Thank you for the information re all. Good to know re head warpage checking if the cam rocks in the center cam bearing. And for letting me know head gasket is a quick job.
 
A head gasket job on a Redblock isn't that bad compared to a modern engine. Remove intake/exhaust manifolds, pull accessory/timing belts. Remove distributor, valve cover, cam, head. That's about it.

I second getting your current head checked for warping. A machine shop can resurface a warped head easily.
 
How do I remove timing belt and put it back togather mantaining the correct valve engine timing? I'm need instructions how to do this. Also belt appears to be in good condition but how do I check belt and if the tensioner is good or requires maintenance?
 
940T Wagon 1993 & 1994 said:
How do I remove timing belt and put it back togather mantaining the correct valve engine timing? I'm need instructions how to do this. Also belt appears to be in good condition but how do I check belt and if the tensioner is good or requires maintenance?
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There are timing marks on the timing covers, it's not complicated to get it all lined up like a modern engine.

I would strongly recommend just installing a new belt and tensioner if you're taking off the old one anyways. They're very cheap and you'll save yourself the effort down the line. If you don't know the last time it was done, it's probably near time to re-do it.

You can technically swap the tensioner without removing the belt. If the old one spins quietly and you really don't want to shell out $30 for a volvo-approved INA tensioner, then I guess you could leave it in there. I've done two tensioners without removing the belt by zip tying each side of the belt together to hold it in place after inserting a drill bit into the tensioner to slacken it up, and then you can just slide the tensioner out and swap it over. Granted, the only reason I had to do this was because I didn't change the tensioner when I did the belt in the first place.
 
NLRegina said:
There are timing marks on the timing covers, it's not complicated to get it all lined up like a modern engine.

I would strongly recommend just installing a new belt and tensioner if you're taking off the old one anyways. They're very cheap and you'll save yourself the effort down the line. If you don't know the last time it was done, it's probably near time to re-do it.

You can technically swap the tensioner without removing the belt. If the old one spins quietly and you really don't want to shell out $30 for a volvo-approved INA tensioner, then I guess you could leave it in there. I've done two tensioners without removing the belt by zip tying each side of the belt together to hold it in place after inserting a drill bit into the tensioner to slacken it up, and then you can just slide the tensioner out and swap it over. Granted, the only reason I had to do this was because I didn't change the tensioner when I did the belt in the first place.
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Right I will install a new timing belt and a new tensioner as recommended.
 
I think the intake & exaust manifold all new nuts should be used. What company makes the best engine gasket and seal sets and the best place to buy?
 
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Led said:
A head gasket job on a Redblock isn't that bad compared to a modern engine.
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These engines are extremely easy to work on. I pulled the intake manifold off the other night in under 10 minutes. I am almost considering doing the head gasket as maintenance while I am in there.


Thermostat leak pic:

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So its a 32 year old car you don't drive, never having done a timing belt. This would be a good time to do a great many things. New intake, exhaust and throttle body gaskets. Inspect Heater hoses, oil separator, idle air control. Clean and lube electrical connections and cables. You will probably need to replace a few exhaust manifold studs. Put in a new manifold to pipe gasket. I don't know anything about turbos but I'm sure there are things to do.
It could be done fairly quickly but if you have the time... I've done three head gaskets and found the 940 FAQ invaluable. I've used FCP Euro, RockAuto and IPD for parts
 
j.pelchat said:
Inspect Heater hoses...
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I would replace the heater hoses and the heater valve as preventative maintenance. Some people upgrade the valve to something from another vehicle. Or maybe try to get your hands on a metal valve if they still make them.

My heater hose just popped on my 1990 740 GLE 16V and I had to get towed home.

The heater valve in my 1991 740 Turbo looks like it is leaking.

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You don't want to end up with a fried engine because a cheap $10 heater valve broke. That is what happened to this engine:

Ayce

Thread 'B230ft no compression timing correct'

Hello Turbobrickers,

this weekend I found a, not running,1992 940 turbo automatic for 500$. Thats less than I have spent so far on +t parts for my 245.But I guess I have two projects now.

Type story is PO drove it on trailer, drove it off, changed oil, started it up and it died.:unsure: I was hoping that it was just that the timing had skipped a tooth, however it must of been timed correctly (I did not get an accurate reading) since replacing the timing belt and confirming it is correct did nothing. I still am able to spin the engine with a wrench without feeling any resistance...
 
j.pelchat said:
So its a 32 year old car you don't drive, never having done a timing belt. This would be a good time to do a great many things. New intake, exhaust and throttle body gaskets. Inspect Heater hoses, oil separator, idle air control. Clean and lube electrical connections and cables. You will probably need to replace a few exhaust manifold studs. Put in a new manifold to pipe gasket. I don't know anything about turbos but I'm sure there are things to do.
It could be done fairly quickly but if you have the time... I've done three head gaskets and found the 940 FAQ invaluable. I've used FCP Euro, RockAuto and IPD for parts
Click to expand...
 
thanks, I dont know how to locate, inspect the oil seperator or how to check idle air control. Do head bolts need to be replaced or can they have threads cleaned and reused? OK re clean and lube electrical connections. How do I know when manifold studs need to be replaced?
 
Leave the heater core valve out, don't know if it works everywhere/for every climate but for me it works. The original was cracked and could have snapped any day.

The hoses going to the oil cooler are also a much neglected item. My advice is to replace them. Inspect the expansion tank too, same with the radiator. No fun to replace the head gasket twice.

When in doubt, original Volvo studs. Those are really good quality. Intake manifold bolts can be reused if you want.
 
940T Wagon 1993 & 1994 said:
thanks, I dont know how to locate, inspect the oil seperator or how to check idle air control. Do head bolts need to be replaced or can they have threads cleaned and reused? OK re clean and lube electrical connections. How do I know when manifold studs need to be replaced?
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The oil separator is the black plastic box under the intake manifold. It will often be packed full of gritty, oily sand stuff. Clean it out. The hoses going from the separator to the intake will likely be baked into brittle plastic by now, replace them.

The IAC just visually inspect and clean out with carb cleaner or something equivalent. Dismount the throttle body and give it a good cleaning as well, it will probably have carbon build up.

Head bolts can be reused as someone already said. Volvo says you can reuse them three times (or something like that?).

This is one of the easiest overhead cam engines to do this job on. No need to overthink it, plenty of people who are pretty dumb have managed it and you can too.

Oh and figure out a crank locking tool for loosening and tightening the crank bolt (or pull the radiator and fan for clearance and send it with the impact).
 
I recommend you buy the crank holder tool. You are also going to need a large breaker bar, a 24mm socket, and possibly a pipe to slide over the breaker bar in order to get that crank bolt off and back on tight.

There have been reports that aftermarket cam and crankshaft seals are leaking soon after installation. You want to buy the highest quality seals that you can for the job.

There have also been reports the blue box OEM Volvo stuff for these cars can be cheap aftermarket parts put in a blue box and marked up.

Make sure to get the round tooth timing belt for that year. Older years are square tooth.

I would do all the cam, crank, aux shaft seals and a new high quality water pump while in there. It is much easier to install a water pump with the head off and get the upper seal compressed well.

Plan on needing to do PCV hoses, vac hoses, wiring repair, heater hoses, gaskets, belts, and probably all the bushings on the accessories too. Don't put those blue URO bushings in there. They will turn to dust in a year.
 
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ortho stice said:
The oil separator is the black plastic box under the intake manifold. It will often be packed full of gritty, oily sand stuff. Clean it out. The hoses going from the separator to the intake will likely be baked into brittle plastic by now, replace them.

The IAC just visually inspect and clean out with carb cleaner or something equivalent. Dismount the throttle body and give it a good cleaning as well, it will probably have carbon build up.

Head bolts can be reused as someone already said. Volvo says you can reuse them three times (or something like that?).

This is one of the easiest overhead cam engines to do this job on. No need to overthink it, plenty of people who are pretty dumb have managed it and you can too.

Oh and figure out a crank locking tool for loosening and tightening the crank bolt (or pull the radiator and fan for clearance and send it with the impact).
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Thank for the explanations!
 
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