20 Most Recent 1998 Cadillac DeVille - Page 9 Questions & Answers

The problem occurred in the past and may not be happening now. Code 420 is for a problem where the catalytic converter is not functioning at full capacity.

Here is a site I just heard of awhile back, pretty good. Code descriptions, symptoms, and solutions for what appears to be every code. Note: sometimes my links don't post first time. If it happens, I'll put in below in "add a comment" section.

head gasket problems can cause leakage of antifreeze into the exhaust through the cylinders and low antifreeze levels can cause an overheat problem due to a leaky head gasket.

A leaky water pump can do the same thing except you'll see a puddle of antifreeze from the o-ring not sealing right.

Blown head gasket seal can help with minor defects in the head gasket seal but not major leaks.

It may be worth the cost to try a head gasket seal solution before replacing the head gasket which is a major procedure.

compression tests identify problems with---head gaskets --- cracked heads , blocks--- valves not seating correctly---worn rings ---cracked pistons--- and general condition on the engine

get code/s from ecm, is it also missing cold hot?

Unless you live in a state that requires an emissions test, forget it. The factory fix is to replaced the converter and internal seals and bushings. These states machines will not let you run a test with the light on.

run fault codes and look for cam/.crank position sensor . Check that the cam shaft is turning (broken belt)

check the care electric fuses there must be burned one in the same time positive wire attached with care body any where wasting the battery

Try put key in ignition turn to on just before it turns over and put battery charger on battery. Let it sit there for 30 min then turn off and do it again for a 5 min , then after the 5 min turn off and try to start it

look in the fuse box may have more than one.

use a code reader to reset the CPU

My book shows 3.0 ltr 1997-01 "V" engine with a timing belt recommended change at 100.000 miles or 60.000 miles under adverse conditions. It shows 3 idler pulleys that should be changed as well and all the cam and crank seals should be replaced as well because oil is the main killer of timing belts.. While you may consider the extra cost to be a burden you will not think so when you get 100.000miles trouble free in the timing belt area . Do not replace any of the items and you run the risk of all that work again in say 30.000 miles

if its under the hood then it is your cooling fans If you need further help, reach me via phone at https://www.6ya.com/expert/steven_a67ead41eb5fc62a

FIRST CHECK FUSE,MAY HAVE POPPED OUT A LITTLE AND NOT MAKING GOOD CONTACT OR THE BLOWER MOTOR RESISTOR IS BAD,LOCATED NEXT TO BLOWER MOTOR,EASY TO REMOVE,2 SCREWS HOLD IT ON AND IT'S PRICEY FOR YOURS.