Knock knock

[DradusContact]

This morning while idling on the drive i heard a quiet 'thud' and another a few seconds later. It seemed to repeat about every 5 seconds. Ive already had the 'heartbeat' noise of the HCV going, which i replaced last year. So it shouldnt be that. Any ideas?

 

[Dal]

Odd. Can you tell when it's coming from? Front of the engine? To one side? Does it do it cold and when warmed up?

 

[DradusContact]

Sounded like in front of me. Once i was warmed up (waiting in the massive que for the runcorn bridge of course) i turned the radio off and i couldnt hear it.

 

[Dal]

As a first step, I'd check your oil level (and condition - if it's too 'gloopy' then maybe the oil pump is struggling when it's cold?) and your coolant levels as they are very heat dependant.

Long shot - but it's not your ABS self test on the way out and continually testing when cold?

 

[DradusContact]

Never thought of gloopy oil. Might be time to get it done. Was lst done last november i think. Ive got two coolant pipes that are in quite bad condition and are dripping a bit, ive been meaning to replace them for ages but havent got round to going up to buy them. Dont think it was ABS test, it wasnt that noise.

 

[Dal]

Maybe your coolant pipes are distorted somehow (if you say they are in bad condition) and have a blockage? That may explain the 5 second interval as pressure builds up, then blasts through the obstruction.

Last november should mean your oil is ok I'd have though - unless you do lots of miles or lots of short journeys.

 

[DradusContact]

Average journey is about 5 miles/ 15 minutes or less. I leave it for a few days at a time as i bike to work 4 or 5 times a week so it may sit there for a few days. Ill get them pipes replaced this weekend.

 

[Peter]

Give the heater knob a twist, see if the speed of the noise changes. What you're describing sounds like the HCV in action.