I have an 85 Bonneville 8 cyl 5.0 with only 39,000 Original miles on it. Engine knocks when at temp with a load on it. (Going up a hill ) Or when at temp at or over 55mph. When shes cold not a problem at all.
When I 1st start the car I can get it to 85 mph without any noise at all. Once it hits temp if I drop under 55 and then give it gas to get back to 55.
It rattles like I have metal bottle caps in the engine.
Changed oil pressure sensor and checked pressure.
Changed EGR valve.
I thought oil pressure first but that was fine.
Maybe heat so I changed radiator. EGR was my last thought. Changed and no change.
Actually took it to a dealership by me to look at it.
They said carbon build up. They used Top Engine Cleaner. Didn't work either.
Since then I've Seafoamed engine. Use 93 oct gas.
And she still knocks. Dealership mentioned it could be mechanical. I can't figure out how that could be, if it runs like it does when its cold.
Thanks for your time. The Boogieman
have the same problem?
Sunday, September 9th, 2007 AT 5:10 PM