Smoking Tuscan
Discussion
Took the Tuscan into work today, all was fine until I parked up at the end of the journey and saw plumes of white smoke billowing out from the N/S bonnet vent. There wasn't a huge amount of smoke, it didn't have any particular odour as far as I could tell, and it did stop of its own accord after about a minute. 
I'm understandably a bit wary about driving her back home this evening - didn't have time to check under the main bonnet, but I'll pop down at lunchtime and have a look inside to see if there's any obvious signs of damage. Any suggestions as to possible causes, and what to look out for?
FYI, the car had a rebuild way back in 2006 but has only done about 15,000 miles since then. Also, the oil level is slightly over the 'max' mark (have only had the car just over a week and it was like that when I picked it up). Oil pressure when cold is around 65-70psi, hot idle seems to be around 22psi. That seems to be a bit higher than normal, but perhaps not excessively so
I'm understandably a bit wary about driving her back home this evening - didn't have time to check under the main bonnet, but I'll pop down at lunchtime and have a look inside to see if there's any obvious signs of damage. Any suggestions as to possible causes, and what to look out for?
FYI, the car had a rebuild way back in 2006 but has only done about 15,000 miles since then. Also, the oil level is slightly over the 'max' mark (have only had the car just over a week and it was like that when I picked it up). Oil pressure when cold is around 65-70psi, hot idle seems to be around 22psi. That seems to be a bit higher than normal, but perhaps not excessively so
Hi Bob/Colin, thanks for the input - I'd say water is probably unlikely to be the cause as the coolant level looks fine. The car did get caught in a rain shower yesterday afternoon, but has since had about 90mins driving with the engine warmed up, so I wouldn't have thought there'd be any standing water left in the engine bay. I'll keep an eye out for any pools hiding in nooks and crannies when I've got the main bonnet off later though, just in case that's the cause 
Thanks everyone for the advice - I think the prize goes to M4tti:
It definitely looks as though the cam cover is leaking oil near cylinder no.1 (if I've got the numbering in the right order). There's quite a bit of residue on the cover in that area, and the beads of sealant are wet to the touch with what looks and smells like oil. I guess that might also explain the smell of hydrocarbons on start-up - I thought it might just be a case of 'they all do that sir', having never driven another Tuscan for comparison, but perhaps a leaking cam cover could have something to do with it...
If I'm feeling brave I might have a go at removing and re-fitting the cam cover this weekend - looks like a fairly manageable job from a quick forum search, with a bit of time and patience. Seems like I could be getting down and dirty with the speed six slightly earlier than anticipated
It definitely looks as though the cam cover is leaking oil near cylinder no.1 (if I've got the numbering in the right order). There's quite a bit of residue on the cover in that area, and the beads of sealant are wet to the touch with what looks and smells like oil. I guess that might also explain the smell of hydrocarbons on start-up - I thought it might just be a case of 'they all do that sir', having never driven another Tuscan for comparison, but perhaps a leaking cam cover could have something to do with it...
If I'm feeling brave I might have a go at removing and re-fitting the cam cover this weekend - looks like a fairly manageable job from a quick forum search, with a bit of time and patience. Seems like I could be getting down and dirty with the speed six slightly earlier than anticipated
Update: I managed to get the car home last night without any dramas, and there was no sign of any fresh oil around the cam cover when I checked at the end of the journey. Having said that, the journey home took less than half an hour and the oil temp only peaked in the high 60s. I'm sure the temperature would have been higher after the morning commute as I'd spent a bit of time stuck in traffic (probably got up to the 80s), so this observation fits with Matt's theory about the leak only occurring at high temperatures when the oil is thin enough to escape.
Just one thought before I start messing with the cam cover - is that an oil hose running around the front N/S corner of the engine and over the manifolds (visible in photo above)? If so, I should probably rule that out as the cause of the leak first... of course if the hose doesn't carry oil then I think I can safely pin the blame on the cam cover.
ETA: I've just posted in the Speed Six forum with a couple of questions re. removing/refitting the cam cover, in case I need to go down that route - any tips would be much appreciated:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Just one thought before I start messing with the cam cover - is that an oil hose running around the front N/S corner of the engine and over the manifolds (visible in photo above)? If so, I should probably rule that out as the cause of the leak first... of course if the hose doesn't carry oil then I think I can safely pin the blame on the cam cover.
ETA: I've just posted in the Speed Six forum with a couple of questions re. removing/refitting the cam cover, in case I need to go down that route - any tips would be much appreciated:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Edited by 8ball_Rob on Friday 15th July 09:01
Hi Nick,
Sounds like a good tip, thanks - I'll give that a go later and see if tightening the bolts has any effect. My favourite part about that plan is that it gives me a convenient excuse to take the car out on Saturday for a decent blast! After all, I won't know if the problem's been fixed unless I run it long enough to get the oil up to temperature
Sounds like a good tip, thanks - I'll give that a go later and see if tightening the bolts has any effect. My favourite part about that plan is that it gives me a convenient excuse to take the car out on Saturday for a decent blast! After all, I won't know if the problem's been fixed unless I run it long enough to get the oil up to temperature
Honestly guys, I leave you alone for like 5 minutes and the whole place falls apart... 
Seriously though, I've been silent all day due to being alternately bent double over the engine bay, bent double over bits of bodywork (scuttle panel) scraping off old RTV, bent double over the workbench scraping off old RTV from the cam cover, bent double over said cam cover applying fresh RTV, and finally bent double over over the engine bay again for good measure. My back is totally fubar.
Long story short, the cam cover was definitely leaking oil around the N/S bolt hole on cylinder no. 1. Putting 2+2 together, this seems to back up Matt's theory (sorry Frank and Mark!). My original description of "billowing" smoke may have been a bit overly dramatic, it was probably closer to the wisps that Matt described. I expect that the apparent lack of odour to the smoke can be explained by the fact that it had pretty much stopped and dispersed by the time I stuck my face in the bonnet vent to have a sniff, plus my sense of smell is rubbish anyway...
Anyway, the cam cover is now back on - pics to follow tomorrow. I'm leaving it to cure overnight, will take it out tomorrow and let you know how it goes! I did fire the engine up just for a minute or two with the main bonnet off, and couldn't see any signs of leaks. Then again, the oil would have been stone cold - the acid test will be whether it survives an extended run with the engine up to temperature
Seriously though, I've been silent all day due to being alternately bent double over the engine bay, bent double over bits of bodywork (scuttle panel) scraping off old RTV, bent double over the workbench scraping off old RTV from the cam cover, bent double over said cam cover applying fresh RTV, and finally bent double over over the engine bay again for good measure. My back is totally fubar.
Long story short, the cam cover was definitely leaking oil around the N/S bolt hole on cylinder no. 1. Putting 2+2 together, this seems to back up Matt's theory (sorry Frank and Mark!). My original description of "billowing" smoke may have been a bit overly dramatic, it was probably closer to the wisps that Matt described. I expect that the apparent lack of odour to the smoke can be explained by the fact that it had pretty much stopped and dispersed by the time I stuck my face in the bonnet vent to have a sniff, plus my sense of smell is rubbish anyway...
Anyway, the cam cover is now back on - pics to follow tomorrow. I'm leaving it to cure overnight, will take it out tomorrow and let you know how it goes! I did fire the engine up just for a minute or two with the main bonnet off, and couldn't see any signs of leaks. Then again, the oil would have been stone cold - the acid test will be whether it survives an extended run with the engine up to temperature
Update, with photos:
While removing the cam cover, the extent of the leak around cylinder no. 1 quickly became apparent. The bolt with the stand-off was positively swimming in oil, confirming that the seal in this area had failed and was allowing oil into the bolt hole. With the cover off, oil can clearly be seen on the mating surface:
Bolt removed, dripping in oil:
Cover removed, ready for cleaning - whoever fitted it previously certainly had a hard-on for RTV:
Cleaned up and ready to be refitted:
Before/after comparison:
Before
After
While removing the cam cover, the extent of the leak around cylinder no. 1 quickly became apparent. The bolt with the stand-off was positively swimming in oil, confirming that the seal in this area had failed and was allowing oil into the bolt hole. With the cover off, oil can clearly be seen on the mating surface:
Bolt removed, dripping in oil:
Cover removed, ready for cleaning - whoever fitted it previously certainly had a hard-on for RTV:
Cleaned up and ready to be refitted:
Before/after comparison:
Before
After
You beat me to it - I was just about to post some close-up pics of the wear on the inside of the cover:
The marks in the first pic are clearly from the timing chain - I'm tempted to order one of those gaskets you mentioned Matt! I suspected the chain was probably catching the cam cover as I know that's a common problem with the speed six, and there is a noticeable rattle that sounds like it could be caused by improper chain/cover interaction...
I'm not sure what could be causing the wear in the second picture - any ideas? The mark looks to be pretty fresh, so I'm assuming it's recent (engine was rebuilt back in 2006). It seems to be aligned with the blue mark visible in the pic below, but there doesn't seem to be anything obvious in that area that could be causing the wear (see O/S cam between cylinders 1 and 2, looks to be halfway between the two cam lobes):
A couple of final points:
ETA: Just went back to re-torque the cam cover bolts, and noticed that the thread is also stripped on the N/S bolt adjacent cylinder 1, where the leak was previously. At first I was confused because I was sure I torqued it up yesterday, but then I remembered that I had to tighten it by hand because my socket isn't long enough to fit over the stand-off. I also made the rookie error of tightening it after I'd reattached the hose bracket and nylock nut, so the resistance I felt must have just been coming from the bracket and hose trying to stop the bolt from turning...! When I realised my error this morning I took off the locking nut, bracket and washers, and then found that the bolt itself just spins freely... I guess that explains the original leak, as that bolt isn't applying any compression
Based on this, I wouldn't be surprised if the original leak reappears pretty quickly. I guess the only fix is to tap the hole out to a larger bore (if this is even an option), or replace the head...??
The marks in the first pic are clearly from the timing chain - I'm tempted to order one of those gaskets you mentioned Matt! I suspected the chain was probably catching the cam cover as I know that's a common problem with the speed six, and there is a noticeable rattle that sounds like it could be caused by improper chain/cover interaction...
I'm not sure what could be causing the wear in the second picture - any ideas? The mark looks to be pretty fresh, so I'm assuming it's recent (engine was rebuilt back in 2006). It seems to be aligned with the blue mark visible in the pic below, but there doesn't seem to be anything obvious in that area that could be causing the wear (see O/S cam between cylinders 1 and 2, looks to be halfway between the two cam lobes):
A couple of final points:
- I have torqued all bolts to 15ft lbs - I couldn't find any specific torque settings for the cam cover bolts, but from reading Peter Sleeman's excellent guide to the speed six this would seem to be the default torque for any bolts that aren't subjected to very high loads.
- The thread appears to have been stripped previously in one of the two rearmost holes, near the oil returns (the one on the O/S). The bolt didn't seem to put up any resistance either when being removed or refitted. I also found that the mating surface on the block at the very rear end had quite a thick layer of RTV left over once I'd taken the cover off, whereas the rest of the surface was pretty clean all the way round. This is likely due to the one stripped bolt in that area, meaning that the mating surfaces aren't being compressed quite as much as they should. How worried should I be about this? Needless to say I'll be keeping an eye out for any leaks from the rear of the cover...
ETA: Just went back to re-torque the cam cover bolts, and noticed that the thread is also stripped on the N/S bolt adjacent cylinder 1, where the leak was previously. At first I was confused because I was sure I torqued it up yesterday, but then I remembered that I had to tighten it by hand because my socket isn't long enough to fit over the stand-off. I also made the rookie error of tightening it after I'd reattached the hose bracket and nylock nut, so the resistance I felt must have just been coming from the bracket and hose trying to stop the bolt from turning...! When I realised my error this morning I took off the locking nut, bracket and washers, and then found that the bolt itself just spins freely... I guess that explains the original leak, as that bolt isn't applying any compression
Based on this, I wouldn't be surprised if the original leak reappears pretty quickly. I guess the only fix is to tap the hole out to a larger bore (if this is even an option), or replace the head...??
Edited by 8ball_Rob on Sunday 17th July 12:22
Lol, the thought had actually crossed my mind 
I wussed out though as this was my first time removing/replacing a cam cover, and I figured I'd be better off concentrating on one job at a time. If I take Matt's advice and upgrade to the viton gasket in the near future, I might tart the cover up while I've got it out again
I wussed out though as this was my first time removing/replacing a cam cover, and I figured I'd be better off concentrating on one job at a time. If I take Matt's advice and upgrade to the viton gasket in the near future, I might tart the cover up while I've got it out again
Touch wood, I'm glad to report that the new seal seems to be holding up OK - it survived a 1.5hr round trip yesterday evening with no signs of any leaks. Oil temp was in the high 70s for most of the journey, peaking at 83. Ran a rag around the edge of the cover when I got home and it came up bone dry, so it looks good so far 
I wouldn't be surprised if the oil forces its way through again at some point near one of the stripped bolt holes, but at least next time I'll know what the problem is straight away and how to fix it...
Thanks everyone for your advice and encouragement, Saturday was pretty stressful but it looks like all the elbow grease was worth it!
I wouldn't be surprised if the oil forces its way through again at some point near one of the stripped bolt holes, but at least next time I'll know what the problem is straight away and how to fix it...
Thanks everyone for your advice and encouragement, Saturday was pretty stressful but it looks like all the elbow grease was worth it!
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