1998 S70GLT what besides Propane to detect vacuum leaks?

macs70GLT · Post by **macs70GLT** » 31 Mar 2014, 12:28

Currently I'm working on my son's 940 to find & fix an audible vacuum leak. (posting here due to common issue with 850 and S70 series).

I hear this high pitched whistle clearly, have been using Propane all over the area with no noticible change in idle. The idle is running high ~ 1500 rpm. I can get it lower running the AC which helps. I have directed the propane at all visible hoses and intake manifold interfaces, also at the injectors.

So far I have replaced a few hoses with no luck. Will continue replacing the old crumbly ones.

Is there something other than Propane that works better in terms of getting the idle to surge?

Thanks - appreciate all the help.

Mike

Post by **rmmagow** » 31 Mar 2014, 12:38

I'm pretty sure I used brake cleaner or spray starter to do this before. Can't remember which or probably both at one time or another.

Post by **rmmagow** » 31 Mar 2014, 12:39

960 got an IAC? That would be my most suspect.

macs70GLT · Post by **macs70GLT** » 31 Mar 2014, 13:06

rmmagow wrote:960 got an IAC? That would be my most suspect.

Thanks rmmagow - I'll look more closely at the IAC. the car is a 95' 940T. The frustrating part is I can hear it clearly, just can't get the source to suck up the Propane - or as mentioned the idle is too high for the Propane to make a difference.

I have brake cleaner as well, probably give that a try tonight.

Thanks

Mike

Post by **rmmagow** » 31 Mar 2014, 14:23

Vacuum cleaner hose to the ear and move it around. It bugger and more flexible than a straw. Length of garden hose might help too. Any longish floppy tube that can be fished around a bit.

Post by **rmmagow** » 31 Mar 2014, 14:25

bigger, not bugger

Post by **jose456891** » 31 Mar 2014, 19:52

I use carb cleaner

macs70GLT · Post by **macs70GLT** » 31 Mar 2014, 23:29

Thanks for the suggestions.

Finally found the leak tonight - it is the intake manifold on the underside by # 1 cylinder.

I used a cutoff piece of garden hose to get close to the area. Then used a can of Fuel Injector cleaner (similar to carb cleaner I think). By the way, I just cut up the short 6' garden hose that goes from the house to the hose spool then replaced it with a new hose ~ $6.

Anyway, just need to get a new manifold gasket & wait for my son to return from his trip. I'm slowly teaching him some of these things as they happen on his car.

Thanks

Mike

Post by **rmmagow** » 01 Apr 2014, 03:24

Sweet! Recent PCV job?

Post by **erikv11** » 01 Apr 2014, 07:45

Ah good find indeed, thanks for posting up with the solution.