1993 240 Moaning On Acceleration

casamig · Post by **casamig** » 08 Apr 2012, 19:25

I appologize if this topic has been discussed in the past, if so, I was unable to find it.

In any case, my 1993 240 makes a monotone moaning like sound when accelerating.

I can not recreate the sound when throttling up in park.

The sound is not present when simply rolling at speed, only when accelerating, from any speed to any speed.

I notice no obvious changes in performance, the car is as slow as ever.

My flame trap is nice and clean.

I cant seem to pinpoint the location of the noise. It seems to come from all over.

I fear it may be my wheel bearings, but wouldn't they make noise at any speed, under power or just rolling?

What can be wrong and how can I identify the problem ie. how do i know if my bearings are bad.

Thanks for your help.

casamig · Post by **casamig** » 09 Apr 2012, 11:58

I had the opportunity to put the car up on stands. Both front wheels turn smothly. They sound somewhat "dry" (sounds more like rotor slightly rubbing shoes than bearings) but offer no real resistance or grinding or bumping.

The suspension seems fine. Tracks straight. Ball joints and tie rod ends seem fine. Brake pads will need replacement soon but operate smoothly and safely with no binding. Rotors are smooth and true.

The noise doesn't seem to affect the actual acceleration.

Transmision shifts up and down fine.

A perfunctory inspection of the exhaust system seems fine although I'd like to have a more detailed look.

I did however drive her pretty hard for the first time ever a few weeks ago (By that I mean about 80 mph, I'm a pretty slow driver so 80 is quite fast for me). Noticed some oil splash/spill/leak from valve cover gasket and oil fill cap. Nothing major from front or rear cam seals.

The noise however didn't manifest until yesterday. It first presented at highway speed with the AC on. Now however, it's present at any speed with or without climate controls.

Again, the flame trap is clean. It's obviously tricky to inspect/replace the seperator box and would prefer to identify the actual problem before spending time and money changing things that are fine.

Once warm, it idles nice and smooth. No stalls or stutters ever so I'm thinking the fuel filter/pumps although old are probably ok.

The car is automatic with aproximately 130K. I'm the second owner and although I am competent tree shade mechanic, this is my first of hopefully many future Volvos.

I am truely in love with this car and hope to keep it.... forever.

Furthermore, my wife and I are expecting our first child in about two weeks. I would very much love to have this problem resolved and have some peace of mind and although I have two other much newer and more reliable cars, I would love to drive my new daughter home in our old Brick.

Thanks in advance for any help.

Post by **billofdurham** » 10 Apr 2012, 12:23

Welcome to Matthew's Volvo Site.

To check the bearings jack up the car, grasp the tyre at top and bottom and push/pull on the tyre. If the bearings are going you will feel the play.

Oil from the oil cap can be cured by putting in a new seal. Easy and cheap. If it is coming from the cover gasket you may be able to stop it by tightening the nuts slightly.

Diagnosing a noise is difficult without hearing it but I would be checking for a piece of paper or a leaf trapped in an air intake such as the radiator grille or the intake for the heater.

Bill.

casamig · Post by **casamig** » 08 Sep 2012, 17:08

Basically took apart the entire intake (good oportunity to clean/inspect) and found no foreign body airway obstructions of any kind.

Furthermore, recently, far from home, she refused to start. Had good spark, motor turned, intermittent hum from primary fuel pump. I found a medium rock and basically banged the entire fuel delivery system with it. I got her to fire and drove home cautiously.

During the drive home however the monotone moaning on acceleration was super pronounced. again, only on gas. no noise when just rolloing.

Put her in the garage, gave her a few days rest. refused to start. And this time there was NO hum from main pump

My thoughts were as follows: 1. fuel filter clogged this whole time. 2. moaning was/is main pump fighting blockage. 3. failure of main pump to hum meant i fried the pump and or the relay.

so, went on ipd, got new relay and filter, installed them and she now runs again.

although i am the second owner, i have minimal maintenance records and the main pump sure did look ancient.

i drove her around the block a few times; felt confident; expressway, moaning returns.

I still seem to think the moaning may be an exhaust leak but despite thorough inspection, i haven't found any.

in any case i'm thinking i'll replace the main pump as insurance.

could the moaning be early signs of my primer (in-tank) pump going?

what can i do?

lindy8_man · Post by **lindy8_man** » 09 Sep 2012, 22:50

I have a similar issue on my 98 S90 However, it is not all the time. Like once every other week. My thoughts are a pinch somwhere in an automatic transmission fluid line. Got the oil changed, and they checked the fluid. IT is burnt, and it should not be. I'll be installing a secondary cooler on another vehicle and a guage. So I figured I would do the same on the s90... Not that hard... I'll be inspecting the lines while I'm pokin around...