Hi all, the 4100 engine in my 84 Eldo has that thumping noise which is still very minor. Which leads me to two questions,
1. I am running 10w40 conventional oil, can I run something a little thicker which would hopefully get rid of the noise, or would that cause the motor to fail faster?
2. Once these motors start making noise, are they in danger of self destructing soon, or are they still fine to drive?
I used 15/40 DELLO or ROTUNDA oil specified for diesel applications for years. The faint thump noise is generally the front crankshaft to bearing clearance. This noise has no effect on engine life.
Thanks for the reply. Good to know that it's just a noise I can ignore, unless of course it gets really loud. I will try that weight oil to see if it gets quieter. Would 20w50 be too heavy? Also, do I need to use ZDDP additive in these engines? Thanks again.
Motor oil already has zddp in it, just in lower percentages than in the past. I would only use a zddp additive in an engine that has flat tappet lifters. My thunderbird has flat tappets and I use Comp Cams break-in additive in the oil. I could be wrong, but I believe the 4100 has hydraulic roller lifters like the rest of the 4.x series..
Wow I would not have thought that any engine made in the 80's would have flat tappets! What a dinosoar... This is what i use in my Thunderbird which is 15 years older and has hydraulic flat tappet lifters: http://www.summitracing.com/parts/CCA-159/
Everything I've read says roller lifters didn't come until the 4.5. And although I haven't my engine that far apart, nothing in the FSM for my 85 4.1 looks like a roller lifter
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Cadillac Owners Forum
4.8M posts
370.4K members
Since 2002
Cadillac Forums is the perfect place to go to talk about your favorite Caddys including the ATS, CTS, SRX, Escalade, LYRIQ, Vistiq, concept and future Cadillac models.