1999 Honda CRV Over-revving on hot days

Tiny
JONNO
  • MEMBER
  • 1999 HONDA CRV
  • 4 CYL
  • 4WD
  • MANUAL
  • 202,000 MILES
We had a problem a year or so ago with our CRV whereby the engine would over-rev, much like an auto when you put the foot down, and this was put down to the clutch needing replacing. And so we did - a new clutch was installed at some considerable expense, however the problem has persisted. Since we've just been through Winter down here in Australia we haven't noticed the problem so much. But now we're heading into Summer and the days are getting warmer, it has become really ugly again.
Either the mechanic lied to us when he told us he'd installed a new clutch (very unlikely since we know him personally), or it is another problem which I am hoping someone will recognise. None of the mechanics I have spoken to about it down here can think of what it might be apart from the clutch.
Friday, September 19th, 2008 AT 9:30 PM

3 Replies

Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Hi Jonno,

Is there enough clutch pedal clearance for the master cylinder?

Does it happen immediately after starting or only after prolonged driving?

What was the quality of the clutch used?
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Friday, September 26th, 2008 AT 11:37 AM
Tiny
JONNO
  • MEMBER
  • 2 POSTS
Can I ask you to explain what you mean by clutch pedal clearance? Do you mean that the clutch needs sufficient clearance so that it engages when depressed almost to the floor or when depressed only a little? Since we replaced the clutch in our CRV, we only have to depress the clutch pedal a centimetre or two before the clutch engages and we can change gear.

This problem generally recurs when we have either been driving for a reasonable length of time (45+ minutes, whether intermittently or otherwise) or if it is a really hot day as we experienced last weekend. That day the clutch was in poor shape from the minute we turned the engine on and it became worse as time went by.

I don't think the mechanic would have installed anything other than a new clutch. Certainly from looking at the invoice we received, the work all appears to have been done correctly, including machining of the flywheel etc. Naturally I cannot say where the clutch was sourced, but I have no qualms about the mechanic who performed the work.

One mechanic I have spoken to this week has suggested the problem might be in the pressure plate, whereby it might not be engaging fully with the flywheel. This would seem to be an obvious answer, especially since the problem only occurs when things have warmed up and metal has expanded in the heat. Even still, to replace the pressure plate would require so much labour as to justify replacing the entire clutch anyway.

Hope that helps?
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Friday, September 26th, 2008 AT 7:35 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Hi Jonno,

A new clutch should have the pedal low and from your description, the master cylinder push rod and clutch pedal does not have enough clearance. Check the push rod free play, it should be able to move freely without the clutch pedal depressed.

Wothout enough free play, the master cylinder piston is not returning fully and this will not allow fluid to return via the relief hole and after driving fo9r some distance, the fluid heats up creating pressure in the clutch system thus the clutch slave is self activating.

If free play is present, the master cylinder is faulty.
Check tht push rod free play, it should be able to move freely without the clutch pedal depressed.
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Saturday, September 27th, 2008 AT 6:45 AM

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