New DSM, new problems: Hissing, leaking

[allthrottle]

I just picked up a near stock '91 FWD GS-T. It has a big 16g on it, and a cut air filter canister, but that's it. I'm having a couple problems that I hope to get some insight on.

When I get into boost at WOT, I hear a hissing noise that almost sounds like it's inside the car, right behind the driver side dash/firewall. I did some searching and found that it could be a boost leak, so I took the car to a reputable local shop. The guy told me if it were a boost leak, I'd have a little bit of stumbling when I let off. Since it has no problems otherwise, he said it could be the upper intercooler pipe at the throttle body expanding. Is this common? I asked about a boost leak test, but he said he didn't think that was the problem, and he didn't want me to waste my money.

I've found three leaks. One looks like it's coming from the bottom of the coolant reservoir, which I'll just replace. One looks like it could be coming from one of the shift levers/rods going into the tranny. Is it common for these to leak? Is is possible to replace the seals on these? The transmission does make a weird grinding noise when cold, at idle, so I think the input shaft is going bad.

The other leak is from the engine.. there could be a few leaks actually. Anytime after I go for a drive and get into boost, I'll see a few drops a few minutes after I park it. It looks like oil was sprayed at the bottom of the back crossmember, but I also see oil under a 1 wire sensor that looks like it comes out of the oil filter housing.

Any advice would be appreciated. I was screwed royally on this car from the guy I bought it from, who mislead me to believe the car had NO problems, so I overpaid. I'm just trying to get these problems diagnosed so I can start enjoying the car

Thanks!

 

[gstryyder]

in my opinion this would make it easier for us on the forum. can you take any pictures? also, i would take some cans of degreaser or brake parts cleaner with some rags. clean up/off as much oil residue as you can see under the car and clean anywhere it looks like something is leaking. when you take it out for a spin after cleaning. look for where the leaks start/ are coming from... maybe take more pics. we can go from there.

1st thing. i think you may have a boost leak. do you have a boost guage? not all boost leaks will always make you car drive noticably different. especially when its a new car to you. maybe you can get a video of the origin of the hissing. but usually i will crawl on top of my motor and under the car and find where the most noise is coming from and go from there. look for any nipples with no hoses attached. or any hoses with no niples attached to the end. they are all over. make sure you look in the back of the engine and back of the engine bay... look all over for em. it is likely to happen.

coolant may be leaking outta your reservoir if it is cracked. check for cracks before you replace it.

as for the oil leak. we will get into that a bit more later. my guess is when he istalled that 16 g he may not have put gaskets on the oil drain tube or something... but time and mre communicating can only help. if i were there it would make it 10x easier. too bad i live so far away.

 

[bagged420a]

You can make yourself a BLT for very cheap. You should look into this because it sounds like the hissing would be a boost leak

 

[jdombrow]

Don't have someone else do it and charge you.

making a boost leak tester is extremely easy and cheap.

$2.00 for 2 pack of valve stems at autozone

$3.00 for a 5 inch piece of 2.5 inch ( inside diameter )rubber plumbing hose that came with banjo clamps on it -- Menards plumbing

$1.00pvc end cap 2.5 inches -- Menards plumbing


IC Pipe Tester

 

[allthrottle]

This is the best I can do right now, the camera ran out of batteries before I could get anymore. These are all from the driver side, around the engines front cover. The turbo and all feed & return lines look clean of any oil, so I don't think any of the leak is from them. It looks like there could be multiple leaks though.

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[90gsx16g]

Is the hissing noise sound kind like a whooosh noise? ### i know some people mistake the sound of a turbo spooling for something else and the sound it makes in your upper intercooler pipe.

- Oil leaking can be from anything.. especially since you bought it from an obvious doosh bag. But Do what they say above me, wipe it off clean. Then go for a short drive stay out of boost. Then check. Then go for a boosted drive if you dont see any oil on your first check.

- Coolant leaks have been coommon all my 1gs, usually the almost 20 year clamps lose there original holding force and began to lossen up allowing coolant to escape. I would just replace them all.

 

[allthrottle]

It looks like the seal around the sensor in the reservoir is leaking. I haven't had a problem with it losing coolant yet, just noticed a few drops here and there and finally found the source today.

But yeah, haha, I've had and worked on turbo cars before so I'm pretty familiar with the sound of one It's just a loud hissing air leak sound that I was pretty sure was boost leak until the DSM "specialty" shop told me otherwise. I'll have to do a boost leak test in the next few days.

Thanks for the input so far

 

[90gsx16g]

It looks like the seal around the sensor in the reservoir is leaking. I haven't had a problem with it losing coolant yet, just noticed a few drops here and there and finally found the source today.

But yeah, haha, I've had and worked on turbo cars before so I'm pretty familiar with the sound of one It's just a loud hissing air leak sound that I was pretty sure was boost leak until the DSM "specialty" shop told me otherwise. I'll have to do a boost leak test in the next few days.

Thanks for the input so far

Haha no problem just post what you find out with the hissing.

 

[wises4057]

if it's a really loud noticeable hissing sound, I'd check your innercooler pipe clamps. had that problem with a 1g, and the clamp on the top innercooler pipe had came loose.

 

[steve]

The oil leaking on the driver side is a real common location since most of the oil seals are right there.
The oil pressure sender is pretty much the lowest point so it all runs down to it and then drips off.
You may have to take the timing belt cover off to find the leak, it looks like it may be leaking from above the oil pan/bottom of the block. That would mean someplace like crank, front balance shaft or tensioner pulley for the "B" belt or the front cover.

 

[allthrottle]

Just an update to this thread;

I was searching a little and found people with a similar noise inside the car that turned out to be related to the 1 way valve inside the brake booster hose. I went out and checked my hose and found that air could pass both ways. The hose looked like a generic piece cut from a spool of hose.

I looked around the closest parts store and home depot today and couldn't find any check/1 way valves that would work, so I'll have to try again tomorrow. Any suggestions on a local place that I should check?

 

[stevo911]

They are a pain in the ass to find. I lost one a few years ago and couldnt find one local had to ebay a new break booster hose it came with the check valve.

 

[stevo911]

I might be wrong but im pretty sure these are generic hoses? Can you go to a junkyard and take the hose off another dsm there?

 

[allthrottle]

Went by a local shop today and they gave me an old cut up hose from a gs-t that still has the check valve. Put it in, no more hissing It had a crack in it though, so I'm hoping it holds up.

 

[wises4057]

try wrapping it with some electrical tape...should help out a bit.