Chain Tensioner Question
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Fleet Mechanic
Joined: Jul 2010
Posts: 1,354
Likes: 31
From: Winnipeg
Chain Tensioner Question
I posted this on another forum since it's more for my 05 Mustang than my 02 F150 but someone here might know so here goes.
My 05 has had cold start-up rattle for 2 years. Lasts 1-3 seconds and disappears. Haven't run car for 3 weeks so I decided to tear into the engine. Removed valve covers and found the right chain tight, however the left chain would lift about 3/8 - 7/16 inch from bottom guide rail.
Question is what holds the oil pressure in the plastic style chain tensioner over long periods of time? I can't see it being the anti-drain back valve in the oil filter. Maybe I'm wrong? Maybe a one-way valve somewhere. I've read these plastic tensioner's have a seal that blows or leaks slightly between the tensioner and the engine block. I know the older steel versions used a ratchet system to hold the chain tight.
One other problem found. The left VCT solenoid connector had oil in it when I removed the connector. I assume there's no way to fix this other than buying a new one. The oil wasn't visible on the outside of the connector so I guess it isn't relative to my rattle problem.
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My 05 has had cold start-up rattle for 2 years. Lasts 1-3 seconds and disappears. Haven't run car for 3 weeks so I decided to tear into the engine. Removed valve covers and found the right chain tight, however the left chain would lift about 3/8 - 7/16 inch from bottom guide rail.
Question is what holds the oil pressure in the plastic style chain tensioner over long periods of time? I can't see it being the anti-drain back valve in the oil filter. Maybe I'm wrong? Maybe a one-way valve somewhere. I've read these plastic tensioner's have a seal that blows or leaks slightly between the tensioner and the engine block. I know the older steel versions used a ratchet system to hold the chain tight.
One other problem found. The left VCT solenoid connector had oil in it when I removed the connector. I assume there's no way to fix this other than buying a new one. The oil wasn't visible on the outside of the connector so I guess it isn't relative to my rattle problem.
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Postmaster
Joined: Oct 2006
Posts: 4,171
Likes: 12
From: SE Texas
I posted this on another forum since it's more for my 05 Mustang than my 02 F150 but someone here might know so here goes.
My 05 has had cold start-up rattle for 2 years. Lasts 1-3 seconds and disappears. Haven't run car for 3 weeks so I decided to tear into the engine. Removed valve covers and found the right chain tight, however the left chain would lift about 3/8 - 7/16 inch from bottom guide rail.
Question is what holds the oil pressure in the plastic style chain tensioner over long periods of time? I can't see it being the anti-drain back valve in the oil filter. Maybe I'm wrong? Maybe a one-way valve somewhere. I've read these plastic tensioner's have a seal that blows or leaks slightly between the tensioner and the engine block. I know the older steel versions used a ratchet system to hold the chain tight.
One other problem found. The left VCT solenoid connector had oil in it when I removed the connector. I assume there's no way to fix this other than buying a new one. The oil wasn't visible on the outside of the connector so I guess it isn't relative to my rattle problem.
<!-- / message -->
My 05 has had cold start-up rattle for 2 years. Lasts 1-3 seconds and disappears. Haven't run car for 3 weeks so I decided to tear into the engine. Removed valve covers and found the right chain tight, however the left chain would lift about 3/8 - 7/16 inch from bottom guide rail.
Question is what holds the oil pressure in the plastic style chain tensioner over long periods of time? I can't see it being the anti-drain back valve in the oil filter. Maybe I'm wrong? Maybe a one-way valve somewhere. I've read these plastic tensioner's have a seal that blows or leaks slightly between the tensioner and the engine block. I know the older steel versions used a ratchet system to hold the chain tight.
One other problem found. The left VCT solenoid connector had oil in it when I removed the connector. I assume there's no way to fix this other than buying a new one. The oil wasn't visible on the outside of the connector so I guess it isn't relative to my rattle problem.
<!-- / message -->
JL
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Fleet Mechanic
Joined: Jul 2010
Posts: 1,354
Likes: 31
From: Winnipeg
Thanks for reply.
Since I removed one tensioner to check for a blown gasket I now understand how it works. The tensioner has a heavy spring behind the plunger that keeps tension on the chain when not running. A blown seal between the tensioner and engine block would have no effect on start-up since I found the tensioner has a bleed hole in the body which would allow oil pressure to drop behind it as soon as the engine is shut off. It may also serve as a bleed to pressure spikes and maybe even serve as a spray for the chain system. Don't know for sure. I could see the blown seal creating problems while the engine is running as there may be a pressure drop created. I don't know if there is also a seal for the plunger as I saw nothing blown out.
The TSB for cold start rattle suggests a cam phaser, oil viscosity, improper filter, etc. but not the tensioner. Since my problem is very intermittent I can't tell which phaser is the problem so I'll have to wait till it gets consistent to troubleshoot.
Since I removed one tensioner to check for a blown gasket I now understand how it works. The tensioner has a heavy spring behind the plunger that keeps tension on the chain when not running. A blown seal between the tensioner and engine block would have no effect on start-up since I found the tensioner has a bleed hole in the body which would allow oil pressure to drop behind it as soon as the engine is shut off. It may also serve as a bleed to pressure spikes and maybe even serve as a spray for the chain system. Don't know for sure. I could see the blown seal creating problems while the engine is running as there may be a pressure drop created. I don't know if there is also a seal for the plunger as I saw nothing blown out.
The TSB for cold start rattle suggests a cam phaser, oil viscosity, improper filter, etc. but not the tensioner. Since my problem is very intermittent I can't tell which phaser is the problem so I'll have to wait till it gets consistent to troubleshoot.
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