i'm about to buy a '91 740 turbo. the car is in immaculate condition and the seller only wants $200, so i figure why not. but the turbo apparently leaks fluid onto the engine and it smokes like crazy. the local volvo garage says they've taken a look at it a while ago and thinks it needs a new turbo entirely, but they want $1300 to fix it. i'm thinking i'd like to look at my options first and consult this very fine forum to see if anyone knows of a good place to buy parts and if anyone knows of any tricks i can do, and if maybe a volvo-specific turbo might not be the way to go. i'm curious if i can upgrade it with an aftermarket turbo system at all.

thanks for the help!

dave

 

If you can get the car for 200 then you should get yourself a junk yard turbo. They pretty much bolt on and off without a great deal of headache.

 

Many more ways to go than a $1,300 "splurge", junkyards are the best for all your Volvo needs of that vintage.

 

Agreed. Go to you friendly neighboorhood junkyard. It might be hard to find a good turbo there. At the junkyard i go to good turbos go fast so you will probably have to go a few times and try to find a car being brought in fresh but if you can find one that would be the best way to go. I wouldn't try to mess around with aftermarket turbos they will cost just as much and will not fit onto your car as well as the original. If you can't find one at a junkyard you would be better off to just have them fix it than to mess around with aftermarket ones.

 

so i've tried to look around at the turbo and man is it messy. i hope i don't have to replace all of the hoses.

anyway, i think i have the mitsubishi model turbo because of the clamp-thingy holding it onto the manifold. i'm planning on taking it off and attempting to clean it out and check for leaks, tube wear and fitting wear. the actual turbo unit looks healthy, so i'm very certain that it's only the pipes that are finished. (one of the air intake tubes wasn't even secured when i went to disassemble the unit)

any ideas on a place to find a turbo rebuild kit for my car? i couldn't find one on a volvo-specific website so i'm guessing i need a turbo-specific website. or if anyone has any tips on cleaning and general rebuilding they would be greatly appreciated.

thanks!

 

okay!

i rebuilt the turbo, changed some vacuum hoses and tried my best to clean out the oil deposits all over the engine (it's still mega-filthy from the oil leaks). then i turned it on to determined if the rebuild worked or not. to say the least, it didn't.

biggest problem is that when, in neutral, i revved the engine up to 7000 rpm to get the turbo to kick in as soon as it hit the red line the car would choke and blow blue smoke. i'm thinking (and i don't know the terminology very well) that the switch in the wastegate isn't working very well. but then again i don't know that much about turbos (learning by doing) so i could be completely wrong. i'm about to give up and sell the thing for half of what i was going to sell it for, but if anyone has any ideas i'd really appreciate it.

thanks!

 

ok...so a rebuild kit didnt work? now...not to say that you messed anything up, doing rebuild kits yourself can go wrong...ive been there done that lol. it could be that one of the oil seals inside the turbo has spluged when you put it all back together. i know ive done that...i would try finding another turbo and bolting that on...getting new oil lines ect. that go to the turbo and see if there is a difference. if so, then the turbo is the problem, if it still smokes...i would say the turbo is not the problem and you may have a head hasket going out. let me know if that helped any.

 

actually i talked to some guys at a local volvo repair shop and they said it was probably vacuum lines. they were right. the car is running pretty well now, the turbo seems to be working with no smoke or overheating. i haven't taken it on the highway so i don't know how it will act at very high speeds, but for an around-town car it's pretty nice. thanks for all the advice guys.

 

so what did you replace?

If it is smoking, the vaccume lines will not have anything to do with it. If the car runs better now after fixing a few vaccume lines... replace all of them and put a new pcv system in the car. It will run and boost much better.
I would also reccomend replacing the turbo oil feed and return lines. If the turbo is also water cooled replace the coolant feed and return lines. If the turbo is only oil cooled, pick up a turbo timer.
If the car is smoking while under boost, the oil seal in the turbo is bad. You can do one of two things. 1) replace the turbo or 2) rebuild the turbo. If you rebuild the turbo, have a turbo shop do it. I highly reccomend deadbolt (send them the turbo, they rebuild and clean it up, then send it back to you).
The best way to create boost while at a stop is to bring the rpms up to where the turbo normally spools, then start to blirp the throttle.

Nick

ps. a boost gauge should be used to see what kind of psi you are pushing.

 

i replaced the vacuum lines that go from the turbo to various places. i have a mitsu turbo, and the boost acuator is controlled by a vacuum line which was very bad. it works now. i'm actually selling the car, there's a post in the for sale section for more details on that.