Cold start knock 2000 Honda Gen 1 CRV ?

[bamx2]

I recently inherited a 2000 Honda Gen 1 CRV ( B20B engine )with 175K miles in very good condition . It has a slight cold start knock (bottom end - rod bearing ?)that goes away within a couple of seconds. The are no obvious oil pressure problems beyond the cold start knock. How near the end is this engine ? Is there anything I can do to make last it longer (move from 5W30 to 10w30 oil - I am in SE US). Is it worth replacing the bearings (pulling oil pan, leave top end alone ). ? - Thanks

 

[JCH13]

I recently inherited a 2000 Honda Gen 1 CRV ( B20B engine )with 175K miles in very good condition . It has a slight cold start knock (bottom end - rod bearing ?)that goes away within a couple of seconds. The are no obvious oil pressure problems beyond the cold start knock. How near the end is this engine ? Is there anything I can do to make last it longer (move from 5W30 to 10w30 oil - I am in SE US). Is it worth replacing the bearings (pulling oil pan, leave top end alone ). ? - Thanks

Why are you sure it's a bottom-end knock?

You might have a slightly constricted oil passage somewhere.

I would try a good oil cleaner run through. I.e. fresh oil + seafoam or ATF, let the engine idle up to operating temps, rev it high in the rpm range a few (4-5) times, shut it down, and do an oil change when it's hot.

 

[SpatiallyAware]

+1 on what JCH said especially for an inherited car like that. "Blowing the stink off" is a very valid thing to do for a just bought car that was never driven hard.

Also I've heard alternators, starters, all kinds of really weird things knock. Use a metal bar as a stethoscope and 'probe' parts of the engine to see if you can 100% verify where the knock is originating.

 

[HarryLui]

It's not using a fram oil filter, is it?

 

[bamx2]

I have done the metal bar / stethoscope observation . I am pretty sure it is a "dry" knock (excessive clearance before oil pressure comes up ) .

I changed the oil with 5W30 oil and a Honda brand oil filter with no effect on this symptom . However the PO (a relative) previously have the oil changed every 3k-4K mi at a quick lube facility so the quality of the oil filters (bad anti drain back valves ?) used is questionable.

 

[basslover1]

I'm not a particular fan of the "quick" engine flushes I just think they're too drastic especially for a motor of that age.

Try running an Auto-Rx cycle through the motor and see what happens. It's like 25 bucks, but it takes about 5k miles to work completely.

I did it on my 1.8T Passat, a motor notorious for sludge issues, and it cleaned it right out. The amount of crud that came out of the engine was amazing, definitely worth it.

 

[JCH13]

FWIW I ran a mixture of 1qt ATF, 1 can seafoam, and synthetic 10W30 through a 200k mile Miata engine after installing it, worked like a charm. I've also done seafoam oil flushes on 215k and 165k mile motors to good effect (reduced or eliminated HLA tick). Of course, YMMV.

 

[basslover1]

FWIW I ran a mixture of 1qt ATF, 1 can seafoam, and synthetic 10W30 through a 200k mile Miata engine after installing it, worked like a charm. I've also done seafoam oil flushes on 215k and 165k mile motors to good effect (reduced or eliminated HLA tick). Of course, YMMV.

I'm not saying they don't work I just don't feel comfortable running that type of flush through an engine.

Seafoam sucked into the engine through a vacuum line on the other hand? Do it often, I love the smoke show.

 

[AdamK47]

Bearing sounds usually do not go away after some time.

 

[thedarkwolf]

Yeah if it goes away it sounds more like piston slap which isn't a huge problem as long as it goes away as the engine warms up.

 

[Arkaign]

All the more reason to save up for an LSx swap 😉