DocTL

If you figure that an oil filter holds roughly .5 quart, he added 2.5, and you .75, you were about 3.75-4 quarts low. That is low enough to cause damage to the engine, but not as severe as running the engine without oil. The only way to determine if there was damage is to 1) inspect as I previously mentioned, or 2) just wait and see if you develop any problems in 10,000+ miles.

I wouldn't bring my car back to them for service in the future. The service department obviously doens't know what they're doing.

crazymjb

Hmm, you think they would have thought of that being a problem. I guess they assume you wont be getting that much travel on your control arms under sain driving conditions. Good to know, if we hit a pothole ill make sure its checkd. But first...To get the car.

KJSmitty

If the light never came on then you probably never starved the oil pump for oil. Whether you have 1 qt or 5 qts in the pan, if the pump never experienced cavitation, "oiling" within the engine would be normal. The main difference is how hot the oil would get. The main reason stock vehicles as well as race cars have certain "volumes / reservoirs" of oil pans is to ensure #1 that the oil pump is never starved due to "drain back" restrictions/oil movement within the engine, and then an amount of oil to achieve proper cooling and time between oil changes etc..
Given your description it's obvious the oil filter had a few "pin" holes etc. allowing oil to leak out under pressure. As long as the filter was not restricting oil from reaching the block/bearings you are good. Most engine oil pressure sending units are located after the filter galley thus the light should of come on if the filter had significantly restricted flow. In all reality if you do the math,,,,, if the Amoco guy installed a new filter and added 2.5 qts to full, like you mentioned - you were “only” 2.5 qts low. The 3/4 qt you added at home was what the filter/lines filled with. The old filter/lines had oil in it thus one can't say you need to add that to the amount "low"...

Either way, your engine is probably fine. Due to the fact that you drove the car for ~two months after hitting the pothole the filter was obviously leaking slowly – most likely very slow to begin with and more so in the last week or so. Thus, your oil level probably exceeded 4 qts for quite some time and then dropped below that amount more rapidly towards the end. Overall, the time spent at or below 3 qts etc. may very well been a short period of time.. Only you know how hard you pushed the car during those two months but if you never “starved” the oil pump,,, (and I know it’s easy for me to say) no harm was done to your engine.

Just my and analysis of your engine/issue. Must have been a hell-of-a pothole…
Ouch!
Best of luck - Cheers

PeterUbers

iTrader: (1)

KJ, thanks for your input -- makes me feel a little better about the whole possible engine damage issue. I guess, as DocTL stated, I'll know in 10,000 miles or sooner if i decide i want the dealer to investigate the inner components of the engine.

Pro Stock John

I think you are okay, but if you are feeling mental about it, get the oil analyzed.

DocTL

As stated by others, you may not have any engine damage, but from my personal experience having had a loss of oil volume in one of my cars, it was not fun. Mind you this was in a 600hp race engine that obviously has tighter clearances than the TL motor. The fact that you had no warning lights come on is a false sense of security. The one thing that I dislike the most about the TL is the lack of proper instrumentation. There is no volt meter or oil pressure gauge. Therefor, we have to rely on a computer display and idiot lights which are not as accurate as manual gauges. I guess I have also fallen victim to being subjected to owning a car that has been dummied down for the masses. (No flame or insult intended.)

I'd keep an eye on the oil level and check it every week. If you start to notice increased oil consumption you may have sustained some internal engine damage. Once again, the way to find out for sure is to have the engine opened up and inspected, which is why I was so concerned in the first place by your mechanic just changing the filter and adding oil.

93SHOcar

Regarding the dealership, have you checked your receipt to see if the p/n of the oil filter is listed? Even if it isn't, you may find that the dealership is using the wrong size filter on all TL's and will acknowledge it. Hopefully, no damage has occurred and this will all be a non-issue. However, getting the dealer to agree to the facts now would make it easier to get them to cover the costs involved if you were to have problems at a later time.

JoganJani

Nice post Peter. Hope there is no engine damage. Before you changed oil, did you observe the the diff. as in how much oil had lost due to cracking this filter before you refilled it? We might do some guestimates on how low the oil needs to go before the light comes on.

PeterUbers

iTrader: (1)

Jogan -- i estimated that I lost anywhere from 2.5 to 3.5 quarts of oil from the tiny crack in the filter...

KJSmitty

I don't have the manual handy but does the TL actually have a "low oil" warning light as well as "low oil pressure"??? My guess is the light is a low "pressure" only. In this case the sensor is most likely set at 5-10 psi (IE if the oil pressure drops below 5-10 psi the light illuminates). If the oil pump was to cavitate long enough to lose significant pressure (causing "possible" damage) the light would have come on.

For PeterUbers,
Does your oil light extinguish quickly upon starting etc.? One way to tell if you have excessive bearing wear or oil pump issues etc. is by how long it takes for an engine to build oil pressure. If the light goes out instantaneously upon starting with no "flickering", all is most likely normal.

Good luck

vash68

2.5+0.75=3.25

Now let me speculate. One detail was overlooked here: when mechanic removed oil filter, he might had lost another quart of oil easily. Which means there was about 1.5 quart of oil shortage

my 0.02

King of Pain

This seems to be the week for reviving old threads. This thread is over 1 year old.

Still good info I guess