hi i have 81 eldorado and its been sitting in my yard for 2 months i replaced the cap, coil and the ingnition module and i started up right away but the motor started to knock whats wrong with it

65

Asked by May 06, 2010 at 04:40 AM about the 1981 Cadillac Eldorado

Question type: Maintenance & Repair

10 Answers

115

depending on the knock .. one of two things .. 1/bad gas - spoiled from sitting for an extended time .. 2/internal piston/rod problem .. good luck .. depending on the car condition, it would be worth fixing .. i've always wanted this body style, black, biaritz !!! good luck

65

thank you for replying and helping me with my problem. if its bad gas would it be best it i let the car run a let it burn all the bad gas because it never knocked before. and that caddy u always wanted is the same caddy that i have it a kick ass car

8,650

I would drain out as much of the bad gas as possible. Then fill it up with some premium and install a new set of plugs. Just be sure to set the right gap.

65

thank you buddy i didnt think bad gas would make a motor knock

8,650

Yeah, the longer gas sits the weaker it gets. It makes it hard for the engine to light it off. Especially with old worn plugs.

65

thanks larry

8,650

No problem. It's good to see someone keeping the classics on the road.

5

it could be a rod if it is in the bottom end of the motor

8,650

He said it didn't do it before when it was running. So unless a bearing seized from sitting I don't think it would be a rod knocking.

Cadillacs of that era will get a knock that sounds a lot like a rod knock, but it may not be. Sometimes a chunk of carbon with fall off the valve and create the noise. Run the car at a high RPM, at the same time pour some water out of a cup into the carb. The small amounts of water will break up the carbon deposit. I've done this many time on cadillacs.

Your Answer

Add photo

Related Questions

Eldorado

Looking for a Used Eldorado in your area?

CarGurus has 392 nationwide Eldorado listings starting at $2,500.

ZIP:

Search Cadillac Eldorado Questions

UK Questions

Are you a UK consumer? CarGurus now has a discussion forum in the UK.

Cadillac Eldorado Experts

#1 spiderblu
spiderblu
Reputation 780
#2 COMETGUY61
COMETGUY61
Reputation 280
#3 Js08016
Js08016
Reputation 270
View All

Related Models For Sale

Used Cadillac DeVille
5 Great Deals out of 1,964 listings starting at $1,600
Used Chevrolet Corvette
289 Great Deals out of 20,545 listings starting at $3,688
Used Chevrolet Camaro
445 Great Deals out of 40,684 listings starting at $3,500
Used Chevrolet Impala
935 Great Deals out of 35,377 listings starting at $1,700
Used Ford Mustang
577 Great Deals out of 42,797 listings starting at $1,699
Used Lincoln Continental
3,774 listings starting at $42,995
Used Buick Riviera
128 listings starting at $2,495
Used Lincoln Town Car
40 Great Deals out of 2,127 listings starting at $1,995
Used Dodge Charger
497 Great Deals out of 30,244 listings starting at $2,275