Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Ricky043 on 09 November 2024, 10:00:10
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After about a months trouble free driving, yesterday was set as the day for my mechanic and I to give the inner sills a de-rust and underseal in preparation for the MOT in early December. When I went to put the car in the garage I noticed a damp oily patch on the ground under the front R/H corner of the car. Opened the bonnet and noticed that the top of the coolant expansion tank was wet on the top. Opened it up, put my finger in the tank, which was full to the top and brought it out covered in a thick brown liquid that was not anti freeze.
I assumed the worst at first, cracked block, blown head gasket (even though the car was still driving great when I parked it up the night before).
Then I remembered the engine oil cooler buried in a water jacket in the V of the engine (don't know who thought that was a good idea!!) so, when my mechanic arrived I started the car briefly to get it up the slope and into the garage.
Change of plan. We assumed it was the oil cooler rather than a blown HG so we (he!) dismantled the manifold and extracted the cooler which was sitting in a little bowl of oil rather than coolant.
Weirdly, upon draining the rad it was only full of coolant, not an oily mixture, so we at least won't have to clear that out.
Don't know the route the coolant takes from the oil cooler bowl but it seemed to go practically straight to the expansion tank and displaced the water, filling up the expansion tank and forcing the oil through the expansion cap.
Anyway, cannot seem to find a new oil cooler on ebay or with a general internet search under the part number.
Any idea where I can get one or is there another option (like just connecting up the two oil pipes that go to the cooler and bypassing the cooler completely?)
I would prefer a new cooler as I don't really want a second hand one.
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You could I suppose try fitting an external oil cooler but that I think would require some fabrication of mounting points for the cooler and different pipe work.have you tried looking to see if there are any coolers listed for the V6 Saab which is at least pretty much the same engine-if not totally so? Other than that you might have to try America a source[Cadillac Catera springs to mind but GM used the engine in other models too].
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Sounds like youve caught it quite early, but there will be oil in the cooling system, even though the rad wasnt full of sludge.
Once its running and warmed up, quite a bit of draining / cleaning / refilling will be needed before its all clear.
There must be still new oil coolers available from somewhere.
Doc Gollum will probably be along soon with a link.
I have always had my doubts if the cooler is needed in this country, particularly on a car that isnt regularly thrashed.
Im not expert enough to recommend doing it though.
It might be worth considering blanking off the pipe connectors on the block ? :-\
Your decision, not mine. ;)
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Certainly in my ownership the car won't be thrashed, so I too question the absolute need for an oil cooler.
I probably wouldn't be happy just blanking the two outlets on the block off, as the pipes clearly make a circuit to the cooler and back again to the block, so unless I knew for a fact this would not be reducing oil circulation, I'm reluctant to do it.
If I cannot get a new oil cooler I'd be happier finding a point somewhere along the two pipes' path to actually cut them and join them together, so the circuit is still maintained. And the close this is done to the top of the engine by the inlet manifold, then there might still be some cooling effect to the oil by running up and down the pipe.
As we have now removed the leaking oil cooler, my preference is to find a new replacement, if there is one out there.
I'll have to dig out the micrometer so I can measure the O/D of the two pipes and try to source suitable pipe connections, in case the hunt for a new cooler proves fruitless.
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the ''oil cooler'' is actually a heat exchanger ie it works both ways round & helps to heat the coolant after starting from cold.
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Unfortunately, after a while, they exchange more than heat
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I got a stainless one from a Vectra, okay used but sound.
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Also worth looking on Saab parts sites, as some Saabs also used the same V6 engine.
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Is there anybody out there who can repair and pressure test the engine oil cooler?
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Countrywoman
I have sent you a PM
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Just been on to a Saab specialist near Chelmsford who got a Saab part number for the oil cooler. There was only one n Europe which was in Sweden at £335 plus VAT and shipping. However, when he sent me the exploded diagram, the oil cooler is completely different in the Saab v6, so a fruitless exercise.
Does anyone know what the thread type and size is where the two pipes go into the cylinder block, so I could just plug up the oil pipes, if I have to, as I seem to be having trouble finding a suitable set of fittings to join the two oil pipes together adjacent to the rear of the inlet manifold
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You cant blank the pipes off as it has to circulate, there were remote kits on the bay when I looked 2 years ago.
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Unless someone could definitively say blanking off the two pipe outlets from the block would not affect circulation I was not going to do it. Think I've found a solution if a new or good second hand cooler cannot be found.
The O/D of the oil pipes are 12mm. I can get 12mm x 15mm compression reducers, which I've ordered. Also ordered a 180 degree bent piece of 15mm copper, so I can cut the 12 oil pipes, fit the 12mm end of the reducer over that and then fit the 15mm x 180 degree bend to the other end of the reducers to connect them so I maintain the circulation. I will have to use a short length of 15mm copper between the reducer and the bend, as the bend is an end feed (soldered) connection, not compression.
But that would work if I cannot get a replacement oil cooler.
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I would urge you not to blank off the oil cooler pipes.
If you joined them up instead in a loop it wouldn’t affect flow.
Personally if I had a failure now I would probably fit a small external cooler
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An extension cooler/remote can be fitted, you need to remove the connections/pipes that are on the oil filter housing, and get the correct pipe work made up, and fit a new cooler in front of the rads, you will need to leave the old cooler in situ,as this keeps the water flow at a flow.
To clean out the sludge, drain system refill with 1L of liquid dish washer soap run for few miles, flush out and repeat a couple of times.
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An extension cooler/remote can be fitted, you need to remove the connections/pipes that are on the oil filter housing, and get the correct pipe work made up, and fit a new cooler in front of the rads, you will need to leave the old cooler in situ,as this keeps the water flow at a flow.
To clean out the sludge, drain system refill with 1L of liquid dish washer soap run for few miles, flush out and repeat a couple of times.
21 times to be precise :D
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pm sent
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I'm going the bypass route.
BTW, someone in the ABS said they are working on a solution for the Omega oil cooler but its not available yet. No suggestion when it may be.
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Got the two cooler pipes out on Friday where they attach to the block.
On measuring the O/D of the male connection that screws into the block, it came out as 17.90 mm on my metric micrometer, which was nothing like any of the BSP, NPT sizes which I was expecting. My mechanic suggested I take the connections to Pirtek in Basildon, to see if they could make up a short bypass pipe to screw into the block mountings. They identified the thread as a metric one (M18 x 1.5) and once they'd done that they made up a flexi hose to connect the two unions together. I was concerned that a bit a rubber hose bent 180 degrees might be susceptible to collapsing internally, but they supplied a hose rated to 20 bar, which feels really solid. Also the total height of the by pass is 130mm,, well within the 190mm clearance from the block face where the bypass mounts, to an adjacent bit of chassis leg.
A very elegant solution and for less than £30.
The two guys in the shop were great and said they are often being asked to make up oil and power steering pipes/hoses for old (and not so old) cars which the car makers no longer support. So well worth a visit. Obviously take your old pipes with you. Pirtek have branches all round the country (and the world) and I'm not getting paid commission!!!
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Good result. :y
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That's a cracking result :y
Failing to visualise the arrangement of the oil cooler in my head whilst sat in the office - would that simply be a male M18 x 1.5 at each end of the flexi?
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Be interesting to see how it copes across all temperatures and running conditions. Sitting in traffic could be interesting.
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In response to Stu.C, there is no oil cooler.
THe bypass pipe made up by Pirtek consists of an M18 x1.5 coupler (threaded at each end) in each of the connections to the block by the oil filter housing. THese are then connected to a flexible hose via 2 crimped connections with nuts that attach to the other end of the coupler. THis will maintain the flow of oil out of the block and back again without going to the (absent) oil cooler.
I'm not concerned about the overheating of the oil in the engine as I don't tow and tend to do journeys of no more than 40 miles at a time. Only time will tell if this set up works without overheating, though it should be okay during the winter, and I wanted to get the car back on the road asap without having to fit an external oil cooler with the associated piping etc.
Posting a pic here is too much of a faff, but if you want to see a picture of the hose (not yet fitted) send me a PM with your email address and I'll email you the pic.
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After we did the oil cooler bypass put it thru the MOT last week and it passed with just one advisory for one rear tyre, which I'm planning to replace anyway.
However, on the journey back from the MOT station we could smell burning oil. Nothing coming out of the exhaust (smoke or oil) and no obvious leak from the new bypass hose, so I'm hoping it was some of the oil from the header tank (which spilled over the engine when we removed it for cleaning) that has found its way onto the exhaust manifold and is burning off as the exhaust gets hot. No loss of oil from the sump as it's still full on the dipstick so hoping the smell will go in a couple of weeks.
Got a bit of a shock when I checked the mileage between MOTs in the last year. Less than 400 miles (not a typo) for about £2500 in repairs. At least I'm not spending much on petrol!
Have to see if it goes longer than 4 weeks now without another issue, otherwise the old girl may be on the way out. I can justifiably spend more money on my old Rover P5B to get that back on the road as it will have a value in excess of £10K when its finished whereas, with the omega, I seem to be just tipping money down the toilet!
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What header tank ???
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Aka coolant reservoir I would presume, which was probably swimming in oil from the failed oil cooler.
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Aka coolant reservoir I would presume, which was probably swimming in oil from the failed oil cooler.
Surely that was removed and cleaned ??? Not doing so would be pretty half arsed.
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Overflowed, or spilt some over the engine bay while removing it maybe ? :-\
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that's what he said earlier and sounds likely for the oil smell (hopefully)
we all know that smell but usually subsides after a while unless it's a current leak.
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Been driving it a bit now and the burning oil smell has gone and no sign of oil loss either. It is noticeable that the engine takes longer to warm up without the oil cooler and so far only seems to get to about 92 degrees on the gauge, whereas it used to run at 95 degrees and would warm up quickly.
However, it has been cold recently.
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Been driving it a bit now and the burning oil smell has gone and no sign of oil loss either. It is noticeable that the engine takes longer to warm up without the oil cooler and so far only seems to get to about 92 degrees on the gauge, whereas it used to run at 95 degrees and would warm up quickly.
However, it has been cold recently.
I did say as much ;) ie it's a heat exchanger, not just an oil cooler :y
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A heat exchanger it may well be, but as I could not find a new replacement (nor 2nd hand at the time), if I hadn't done the bypass, the car would still be sitting partly dismantled in my garage and undrivable, waiting for a mythical oil cooler, whereas now it's been MOT'd and is back on the road.
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I wonder if there's space to fit the external cooler from the Desmond?
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I would suspect a lazy Stat for the engine temperature issues.
Can see the lack of "oil cooler" means it will take slightly longer to get up to temp. but nothing beyond that.
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i'm thinking thermostat too . an engine will warm up normally in under 10 minutes and i wouldn't think the oil would be warmed up in that time to affect the coolant temp .like you say it's a heat exchanger so i would think that without the oil cooler the warm up time would actually be quicker !
the thermostats on these can bleed through and not seal well as they age anyway probably not helped if it's had a load of gunge running through it !
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True. If its had a leaky oil cooler, the Stat should be changed as a matter of course. :y
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silly question also but .....
when you did the bypass you did seal the actual original oil cooler connections ? if it was leaking internally it would now be slowly pushing coolant (and old oil) out of the cooler ?
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There are no oil cooler connections to seal. We detached the two oil pipes that ran from the block (by the oil filter housing) up to the cooler and back again. We replaced them with a hose that links the two outlets on the block together, so the oil just comes out of the block and back into it again.
Not really concerned about the Stat being bunged with oil. What surprised us when we removed the header tank (coolant reservoir for the pedants amongst us) was that although it was full of oil, no oil appeared to be anywhere else in the cooling system.
After fitting the bypass and running the car for about 20 mins there was a slightly oily residue in the top of the header tank, so we removed it again and cleaned it out. Upon reinstallation, no further oily residue has appeared, so I really cannot work out how so little oil managed to get circulated around the cooling system given the header tank was completely full of oil and there was oil in the valley that the oil cooler sat in. Not sure how much oil had been lost but it had been at the full mark on the dipstick when I last checked it, but was only just touching the very bottom of the dipstick after the leak was discovered. I had only done about 15 or so miles since I last checked the water and oil levels which were both normal, so it may be, as someone suggested previously, that I caught it early enough to stop it getting circulated around the cooling system.
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sorry for confusion . so is the oil cooler still in the head ?
if so . i meant have the connections been sealed with caps (or the old pipe ends ?)
if the old oil cooler is still in the head what stops water escaping from it if it's indeed leaking internallly ?
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The header tank is the highest point in the system so it stands to reason that the oil will float up to the top :y
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There are no oil cooler connections to seal. We detached the two oil pipes that ran from the block (by the oil filter housing) up to the cooler and back again. We replaced them with a hose that links the two outlets on the block together, so the oil just comes out of the block and back into it again.
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sorry for confusion . so is the oil cooler still in the head ?
if so . i meant have the connections been sealed with caps (or the old pipe ends ?)
if the old oil cooler is still in the head what stops water escaping from it if it's indeed leaking internallly ?
I think the question that cam.in.head is asking is, he knows that you’ve bypassed the oil cooler pipework but is questioning whether you removed it completely and just left the gulley empty.
If you’ve removed the oil cooler completely, I believe he’s asking how you sealed the cover plate holes. You know, the holes in the cover plate where the now non-existent oil cooler pipes used to go. :-\ That’s my interpretation of his question anyway. :-\
(https://i.ibb.co/DHGJ4kmW/IMG-2025-01-29-195434.png) (https://ibb.co/mVvjJtdT)
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I’d hazard a guess that the oil cooler was flushed out, put back in purely for the purpose of the water gulley cover plate seal and the pipework removed as it was no longer required to carry oil. This would mean that the oil cooler was just sat there doing nothing as it has been bypassed but the cover plate would still be sealed from leaking water. :-\
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But if it has a hole in it (which seems to be the case as it was leaking oil into coolant) then whats to stop coolant now leaking into it and then coming out the top of it, if the inlet / outlet havent been blanked off ?
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But if it has a hole in it (which seems to be the case as it was leaking oil into coolant) then whats to stop coolant now leaking into it and then coming out the top of it, if the inlet / outlet havent been blanked off ?
Which is why cam.in.head asked the same question I believe. :y
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yes that's it
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Yes we removed the oil cooler completely. Had we left it in situ but disconnected from the oil supply, there was the obvious risk of water getting into the oil cooler via the leak and then out of the two large pipes that that took oil to and from the cooler, so we would have had to block those too. As the thread on one of the connections was stripped, making a water tight connection would have been problematic, so why bother for a non functioning oil cooler?
We removed the cooler completely and sealed up the two large holes in the top plate with a heath robinson concoction of penny washers over the holes on each side with a 12 or 14 mm nut and bolt to hold them in place, with plenty of mastic both sides and between the washers, to hopefully stop leaks from the valley where the cooler used to sit. THe top cover was also sealed before its bolts were tightened.
No signs of water leaks or water loss so far, so appears to be working. With the cooler removed then the water will flow unrestricted into the valley and out again, so this faster flow of coolant may contribute to the slower warm up. But I'd rather it run cooler than hotter, and the weather has been cold, so that might be responsible. I'll know as the weather warms up.
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Hopefully all good for a while then. :y
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the ''oil cooler'' is actually a heat exchanger ie it works both ways round & helps to heat the coolant after starting from cold.
Hi Andy, with regards mine also broke and spilled oil into the coolant reservoir. And like you I also sought a replacement without success. I then bought an air cooled one off of ebay,this failed spectacularly spilling oil all over the road. I recommend sourcing a 25 row AN10 from Speeding costing £64.53. If wish to connect directly to the input/output of the cooler,You will need AN10/BSP coupler for connection to where current output/input pipes go to the oil cooler.