HT4100 4.1, 4.5, 4.9 Discussion, 4.9 ticking when cold in Cadillac Engine Technical Discussion; 1991 DeVille, 4.9, 117,000 miles. Runs great. BUT, when the engine is cold it ticks. Not a ping, but the ...
1991 DeVille, 4.9, 117,000 miles. Runs great. BUT, when the engine is cold it ticks. Not a ping, but the same noise as when a car is low on oil. I have tried different viscosities (10w-30, 5w-30, 20w-30) different oil additives, different filter brands, to no avail. I know when it gets summer, the ticking will stay away until fall, but it continues to bother me. It ticks for about 3-5 minutes after the first start of the day, and depending on how cold it is outside, it can be very loud.
5 quarts and the dip stick says full. It does not burn oil at all, and I change oil every 3,000 miles. I have owned this car for a year, and it has done it from day one when the weather is cold.
All of my 4.x engines have ticked. are you sure it is coming from the engine and not the accessories? the ac compressor clutch when disenguaged might make a sound similar to what you described. still it dosn't sound like something to wory about.
Next time you're about ready to change the oil. Add a quart of transmission oil to the crankcase and drive it like you stole it. ATF oil is high on detergent and can clean the varnish out of the lifters.
Every time I tried to get high RPMs, I would get a check engine light. Any help would be appreciated. I found a post on this site that said to drive in a lower gear with high RPMs for a while with MMO, but that gave me a check engine light or maybe a transmission warning light, I don't remember for sure.
Hang on, this "tick" might actually be the No. 1 main bearing when you first start it--in other words, don't worry about it. I've had 2 4.9s and they both made a slight noise when cold. If the noise is more like a knock than a tick, this is probably your issue.
I am also plagued with the infamous 4.9 knock which is clearly evident at low speeds under a load (going up my driveway for example). This is completely different. This is a distinct ticking noise that happens when it is colder than 50 degrees, and goes away when the engine warms up. If the engine is warm, it does not do it at all. Luckily, when it is warm is when the main bearing starts knocking, so I don't have to worry whether the engine is running or not. I just turn down the radio and listen to the ever present knock.