Engine knock after oil change start-up...is this normal???

juiced_94gt

Active Member
Mar 30, 2005
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Southern California
Just did the first oil change in the 02 GT since i bought it last month, i put in 6 quarts of mobil 1 5w-30 oil, and when i started the car up it knocked for a couple of seconds...is this normal? is it because there wasnt oil pressure at first? my 94 GT never knocks after an oil change and this is my first modular oil change ever.
 
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What kind of oil filter did you use? The manual calls for strictly Motorcraft filters, even states using a different oil filter may cause a little oil starvation on cold starts, which could definatly cause a knock.

But, there are quite a few people that run other filters without a problem, but there are some filters that are better than others... but ill keep running Motorcraft.
 
Very normal. When you drain the oil, you uncover the oil pickup in the sump and allow air into the system. It takes a few seconds for that air to make it through the engine, bearings and all.

You won't hurt anything by letting it idle through this but you can do this to lessen the pain:

Before starting, floor the gas pedal and hold it there. Crank the engine. It shouldn't start (the PCM goes into clear-flood mode and doesn't inject fuel when cranking with the pedal floored). Crank the thing for a good 10 seconds. This will help move oil into the system...

Release the pedal and allow the car to start. Hopefully, the knocking won't be as loud nor last as long.
 
BurningRubber said:
What kind of oil filter did you use? The manual calls for strictly Motorcraft filters, even states using a different oil filter may cause a little oil starvation on cold starts, which could definatly cause a knock.

But, there are quite a few people that run other filters without a problem, but there are some filters that are better than others... but ill keep running Motorcraft.
thanks guys, i used a mobil 1 filter, should i use a motorcraft next time instead?
 
i feel stupid for answering this thread, but yes its normal the oil filter and ports have to fill up with oil. and with that happening it has a delay on pumping the needed oil to the whole system for the split second it happens. you should pour all but one quart of oil in till you run it to make sure you dont over fill it and then once it is pumped up let it sit check it again and then if needed pour the needed amount in. that way you dont accidently over fill. this is a bigger problem with chevy's
 
trinity_gt said:
Another thing you can do is prime the oil filter before installing it by pouring clean oil into it before installing it...
But don't keep adding oil till it's full as you'll end up dumping half of it getting the filter on, as Ford though it was a good idea to mount the filter sideways. Before you screw on the filter, spread a bit of oil on the o-ring as its much easier to tighten correctly by hand and also makes filter removal easier.
 
CanadaStang said:
But don't keep adding oil till it's full as you'll end up dumping half of it getting the filter on, as Ford though it was a good idea to mount the filter sideways. Before you screw on the filter, spread a bit of oil on the o-ring as its much easier to tighten correctly by hand and also makes filter removal easier.

Not only is it sideways but it's directly over the steering rack. :nonono:
 
DTNODYA said:
Not only is it sideways but it's directly over the steering rack. :nonono:
LMAO even in my 94, it gets all over the place, k-member, rack, and face if im not careful lol, well as long as its not hurting anything, like i said, it has never been a problem on my 5 liter but hey this engine runs 2 thousand times smoother than any 5.0 i have built :nice:
 
you dont have to stick purely to motorcraft. ford puts that in the manual because they make money off the parts. you can safely use Purolater, Wix, Napa, Carquest. the motorcraft filters are made by Purolator. although the FL-820s has a very nice construction.
 
If it knocks every time you start up, change filters. Some have bad anti-drainback valves on them.. I've had several Mobil 1's that did that to me. I just use Motorcraft since then.
 
bdcardinal said:
you dont have to stick purely to motorcraft. ford puts that in the manual because they make money off the parts. you can safely use Purolater, Wix, Napa, Carquest. the motorcraft filters are made by Purolator. although the FL-820s has a very nice construction.


I dunno man, Motorcraft oil and filters are well priced IMO, compared to some of the other brands that are along the same lines.

I understand about the company wanting to make money, but im sure all the other car makers do the same. As long as its not jacked up in price I have no problem with buying Motorcraft parts.
 
if you had read his post he is only complaining of a knock on startup right after an oil change. i do about 5-6 oil chagnes a day at my work and almost every car does that. its almost impossible on most cars to fill the oil filter with oil when installing it because of the angle of the filter on the block. fords are some of the worst at this. the knocking goes away after 3 or 4 seconds and casues no damage whatsoever. also priming the oil system on most cars is a waste, just fire it up and the pressure builds right away.