98 Ls400 Engine Noise...

[jigmaster flash]

2 questions that i'm hoping someone with a bit of MK4 engine knowledge can help me with:

1) Noisy aircon clutch ? - intermittent screechy noise when a/c is off, quietens down to almost nothing when aircon is switched on. I replaced serpentine belt last week to try and reduce the noise, but if anything its noisier since. My immediate thought was aircon clutch bearing gone bad ? anything else I should check before wrestling with pulleys and bearings?!!!

2) Ticking from rear of engine - quite a noticeable ticking from each side of rear of block, volume is constant regardless of whether at idle or with revs - thought it was the injectors so I ran some injector cleaner through last week and seems louder since.

I mentioned it to my local mechanic, and he told me not to worry about the ticking injectors, reckons they always get loud with age and the cleaner they are the louder they'll be.

Anything for me to check before I try and ignore the ticking?!!

been fixing all the little problems that came with the car over the last 2 weeks, these are my last two to fix!!! (hopefully!)

[black400]

Re ticking , could be dirt in the lifters, but a quick google also points to loose manafold bolts?, low trans fluid , not sure about last two will do more reseachfor you, i had this on my 7 series and a oil change fixed it.

But would like to gather more info for you.

[black400]

not finding that much info , you should check out Lextreme they have a v8 forum. i will keep looking for you.

[bookend]

If the bearing in the air con clutch has gone you will get the noise wether the ac is on or off.

If the noise is only there when the ac is on then the noise is comming from the compressor.

[cleverdick]

2 questions that i'm hoping someone with a bit of MK4 engine knowledge can help me with:

1) Noisy aircon clutch ? - intermittent screechy noise when a/c is off, quietens down to almost nothing when aircon is switched on. I replaced serpentine belt last week to try and reduce the noise, but if anything its noisier since. My immediate thought was aircon clutch bearing gone bad ? anything else I should check before wrestling with pulleys and bearings?!!!

2) Ticking from rear of engine - quite a noticeable ticking from each side of rear of block, volume is constant regardless of whether at idle or with revs - thought it was the injectors so I ran some injector cleaner through last week and seems louder since.

I mentioned it to my local mechanic, and he told me not to worry about the ticking injectors, reckons they always get loud with age and the cleaner they are the louder they'll be.

Anything for me to check before I try and ignore the ticking?!!

been fixing all the little problems that came with the car over the last 2 weeks, these are my last two to fix!!! (hopefully!)

1. Possibly a dry tensioner bearing - maybe the extra load from the compressor increases the tension in the serpentine belt which is enough to stop the screeching.

2. What grade of oil are you using? (Too thin maybe?) And is your EGR pipe OK?

Just a few thoughts based on guesswork...

[jigmaster flash]

If the bearing in the air con clutch has gone you will get the noise wether the ac is on or off.

If the noise is only there when the ac is on then the noise is comming from the compressor.

makes sense, but only noisy when a/c is OFF....

2 questions that i'm hoping someone with a bit of MK4 engine knowledge can help me with:

1) Noisy aircon clutch ? - intermittent screechy noise when a/c is off, quietens down to almost nothing when aircon is switched on. I replaced serpentine belt last week to try and reduce the noise, but if anything its noisier since. My immediate thought was aircon clutch bearing gone bad ? anything else I should check before wrestling with pulleys and bearings?!!!

2) Ticking from rear of engine - quite a noticeable ticking from each side of rear of block, volume is constant regardless of whether at idle or with revs - thought it was the injectors so I ran some injector cleaner through last week and seems louder since.

I mentioned it to my local mechanic, and he told me not to worry about the ticking injectors, reckons they always get loud with age and the cleaner they are the louder they'll be.

Anything for me to check before I try and ignore the ticking?!!

been fixing all the little problems that came with the car over the last 2 weeks, these are my last two to fix!!! (hopefully!)

1. Possibly a dry tensioner bearing - maybe the extra load from the compressor increases the tension in the serpentine belt which is enough to stop the screeching.

2. What grade of oil are you using? (Too thin maybe?) And is your EGR pipe OK?

Just a few thoughts based on guesswork...

1) Must say I think your on the right lines , my first thought was it must be a belt tension issue but was a brand new belt and tension/idler pulleys seem to be ok...... Worth trying another belt?

2) same syn 5w/30 that its had last 2 oil changes - but must say it seems louder since I changed oil/plugs last week ...(its very cold here at the mo, but ticking doesn't quieten as engine warms)

Haven't checked EGR pipe - where is it located?

[black400]

Just a taught , check there is not to much oil / or little as this overfull played haveck with my otherhalfs car , sounded like a diesel at one stage.Ive have been on FOUR lexus forums no joy.

[jigmaster flash]

Oil level is correct Martin, was my first check!

I'll live with it for a week or two and see if anything changes that might give me a better idea as to the cause.

I'm almost convinced the belt noise is a belt tension issue now, (which may or may not be caused by one of the aux pulleys), so when I can bear the cold i'll be pulling the belt off and going through the pulleys and changing the belt again.... Hopefully the noise is just appearing at the AC pulley rather than being caused by it!

[black400]

At least nobody recommended WD40 lol

[black400]

At least nobody recommended WD40 lol

[jigmaster flash]

I nearly covered everything in it out of frustration, but decided not to at the last minute :)