Engine 850: B5254S/2.4/20v: Head gasket done, lump rebuilt, exhaust stinks

[dinky1]

Hi guys,

First of all this lump is in a Renault safrane and is technically the B5254FS (F being fuel injected).

So the original engine went wrong (now sitting in storage), cooling failed HGF followed.

Dropped another engine in (this one hadn't run for a few years and was on a pallet outside but started almost instantly), similar thing. Stripped it down, gasket on this was rusted away.. ordered in the genuine Volvo parts, head skimmed, put back together.. in the process my torque angle gauge came apart, rather than leave that one built tightened I loosened it. Volvo dealer said they've reused bolts..

Went with cardboard for the angle tightening on the next attempt..

Upgraded the hydraulic tensioner to an automatic one in the process.. something that I thought was a Renault modification but the bolt hole was already in place by Volvo..

Got it running, cooling still shot, found that fault, car went through an MOT for the first time in 12 years - but they did struggle on the emissions.

It has a brand new catalytic converter from motor parts direct but this didn't want to seal up properly against the flexible downpipe but wasn't a big issue - MOT tester was fine with it but it only cost £90.. Maybe not the best quality.

Exhaust has been rattling a bit and getting worse but the exhaust absolutely STINKS. There's clearly something very wrong with it.

I'm starting to wonder if there is something else going on here mechanically inside the engine like blocked oil channels in the pistons and Conrods causing metal to burn? - engine hasn't lost any power but it is losing coolant. On that note I had no idea the thermostat housing needed two gaskets so it only has one.. But I've also seen evidence of a leak by the radiator too so it might not be burning coolant (but it might! More investigation needed there..)

Anyway.. this exhaust stink is my main concern, it's clearly awful and surrounds the entire car when crawling in first or stationary. Can't say it smells sweet, more of nasty chemicals maybe even metal? Not nice whatever it is.

Also I've seen black water drops coming off one of the exhaust u bolts..

Any ideas where to start? - money is really tight so need to check the cheapest stuff first..

Don't really want to waste the car, took over a decade to get back on the road!

[ITSv40]

Originally Posted by dinky1

Hi guys,

First of all this lump is in a Renault safrane and is technically the B5254FS (F being fuel injected).

So the original engine went wrong (now sitting in storage), cooling failed HGF followed.

Dropped another engine in (this one hadn't run for a few years and was on a pallet outside but started almost instantly), similar thing. Stripped it down, gasket on this was rusted away.. ordered in the genuine Volvo parts, head skimmed, put back together.. in the process my torque angle gauge came apart, rather than leave that one built tightened I loosened it. Volvo dealer said they've reused bolts..

Went with cardboard for the angle tightening on the next attempt..

Upgraded the hydraulic tensioner to an automatic one in the process.. something that I thought was a Renault modification but the bolt hole was already in place by Volvo..

Got it running, cooling still shot, found that fault, car went through an MOT for the first time in 12 years - but they did struggle on the emissions.

It has a brand new catalytic converter from motor parts direct but this didn't want to seal up properly against the flexible downpipe but wasn't a big issue - MOT tester was fine with it but it only cost £90.. Maybe not the best quality.

Exhaust has been rattling a bit and getting worse but the exhaust absolutely STINKS. There's clearly something very wrong with it.

I'm starting to wonder if there is something else going on here mechanically inside the engine like blocked oil channels in the pistons and Conrods causing metal to burn? - engine hasn't lost any power but it is losing coolant. On that note I had no idea the thermostat housing needed two gaskets so it only has one.. But I've also seen evidence of a leak by the radiator too so it might not be burning coolant (but it might! More investigation needed there..)

Anyway.. this exhaust stink is my main concern, it's clearly awful and surrounds the entire car when crawling in first or stationary. Can't say it smells sweet, more of nasty chemicals maybe even metal? Not nice whatever it is.

Also I've seen black water drops coming off one of the exhaust u bolts..

Any ideas where to start? - money is really tight so need to check the cheapest stuff first..

Don't really want to waste the car, took over a decade to get back on the road!

Black water dripping from the exhaust joints when cold is normal - particularly if they are not 100% sealed.

Recently 'er indoors Mini Cooper started randomly throwing emission codes.

I replaced the two oxygen sensors and after a while the codes returned. Replaced the fuel filler cap, made sure there were no leaks in the induction piping and went through everything that I thought it could be. The car ran perfectly apart from a smelly exhaust - most noticeable when fully warmed up and ticking over when stationary. It still kept throwing codes. My son then read the codes with a proper BMW reader and the message was: Cat F*cked! Replaced the cat with a genuine Cat supplied by a BMW dealer and all is now good. Car is now so responsive and the exhaust is immaculately clean.

I suspect your problems are the cheap Cat.

[dinky1]

Ok thanks for that.

Also wondering about the lambda sensor possibly playing up too, spark plugs are black and sooted up - only put in brand new in February and the car has only done 600 miles in that time. I'll have to get that out after xmas day.. New air filter has been ordered.

Did cylinder pressure test today, cylinders all returned a clean bill of health;
1: 13.8
2: 13.8
3: 13.8
4: 14
5: 13.8

All 5 at the top of the green range on my gunson tester so I'm happy with that.

Also topped up the coolant, ran it for a good half an hour, (probably more) no stench today but it was very breezy. No visible coolant leak either and the coolant level went up above the max mark as it should. Later heard the pressure release cap venting (after engine was turned off). I did though tighten the radiator pipe a little but i still have a hunch that one seal behind the thermostat is probably still leaking (you'd think volvo parts would have told me i needed two).

Will crack that lambda sensor out in the next few days and take a looksie at that. Had this car 15 years, it was off the road 12. Hopefully it's not back in the last chance saloon again..

[IainG]

Hi

No visible coolant leak either and the coolant level went up above the max mark as it should.

Surely the max level is just that. It is the max level for when the system is hot?

[SteveSarre]

(I know yours is for a Safrane, and Renault might use a different thermostat housing).

The normal Volvo thermostat setup only needs one seal. It has a groove on the inside so the thermostat sits in the groove and then the housing compresses the seal, sealing both sides of the seal against the thermostat.

Steve

[dinky1]

Originally Posted by IainG

Hi
Surely the max level is just that. It is the max level for when the system is hot?

I understood the max mark to mean the maximum coolant level when cold? - But i'll admit you've got me thinking now and it is entirely possible i've misunderstood that. It would be a little embarassing after 15 years of us having the car lol.. will check the manual in a minute when i can find it. Frustrating thing is we've had three of these cars and i've never lobbed any of the manuals but do you think i can find one in the owners wallet? lol. Anyway thanks for this idea, you may be onto something.

Either way it still leaks somewhere... but more, the exhaust stinks. Even with the old cat which rattled like a tin of nails.

Originally Posted by SteveSarre

(I know yours is for a Safrane, and Renault might use a different thermostat housing).

The normal Volvo thermostat setup only needs one seal. It has a groove on the inside so the thermostat sits in the groove and then the housing compresses the seal, sealing both sides of the seal against the thermostat.

Steve

Apologies if i didn't make myself clear, the thermostat housing bolts onto the head with 3 bolts. Between the housing and block there should be two gaskets, I didn't realise this and only put one in.

Pathetically, i've had three of these engines, can't remember the situation with the first one i dismantled (think i left the thermostat housing attached) but the two engines i have now both definitely had two gaskets (the original engine that's now in storage and the replacement that i tore from another safrane i had). Both of these had two gaskets between the head and the thermostat housing.