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2005 Jeep Grand Cherokee Oil Light on Cold Start

New user here. I have a 2005 Jeep Grand Cherokee (225,000KM). I recently had some work done and one thing identified was an oil leak which they repaired.

However one issue persists: When the engine is cold (first start of the day), the oil light comes on and stays on until I turn off the engine. Usually, any other starts that day, the oil light will not come on.

Any suggestions? Thanks in advance!

Assuming this is the oil pressure light, the first thing you want to do is have a mechanical pressure gauge hooked up so that you can see the actual pressure and find out if the light is accurate. Unfortunately, if the pressure really is low and you’ve been driving while the pressure is low, this could have damaged your engine.

The oil level is correct, I assume?

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+1 to lion’s post.
If it turns out that the pressure is actually fine, and the level is good, the first next place I’d look is at the relay that turns the oil pressure warning light on. That may be hanging up.

Chrysler products of this vintage frequently did this. My 2003 Town and Country and 2004 PT Cruiser bot h did this and the cure is a new oil pressure switch. I think they were about $12 each.

Thank you for the answers. I have a follow up that might be related.

The Jeep is now making a tapping sound that increases upon acceleration. It was not doing it when I picked it up from the mechanic a week ago but has started the last couple of days. The oil light continues the issue as above, going off after the Jeep is re-started subsequent times during the day (we are in a deep freeze here so if it sits long enough, oil light will come back on for subsequent starts, but only if the Jeep has been sitting cold for some time).

Thoughts? (And thanks again!)

Because that tapping sound is…ominous…I would suggest that the only driving you should do at this point is directly to the mechanic’s shop.
But, before you do that…have you at least verified that the oil level is where it should be?

And, are you sure that the oil is of the correct viscosity? Oil that is of too high a viscosity can produce this exact symptom during very low temperatures because it isn’t circulating properly through the engine.

One suggestion I’ve heard relates to an exhaust leak. My mechanic indicated one issue that he hasnt fixed yet. Keep in mind, Im the opposite of a car guy.

He was going to replace the transmission manifold cover (I believe) but when they started he found two broken studs but could not reach them to drill out. He told me he has to remove the engine so I am to go back in a couple of weeks when he has more time. He indicated that there is an exhaust leak and wants me to be careful driving it (have windows open a crack etc).

Also, told me the PCV pipe was brittle and fell apart. They taped it as a fix because the part was on back order due to a blizzard in the area.

Could any of those issues be related?

Is there an oil light and a gauge on the Jeep?

Oil temperature gauge is always normal. But oil light comes on when starting it cold (first thing in the morning or sitting for a long period of time). On subsequent starts up, no oil light.

I will verify oil pressure. But I did not think of that since it just came from the mechanic who, among other work, did an oil change.

I should also say, the ticking sound was apparent previously and upon getting it back from mechanic a week ago, it was gone. And the last two days it’s back and louder. It increases in volume and speed of tapping as I accelerate. When idling its apparent but not as fast or loud. Sort of like if you held a playing card in a bicycle spoke - the faster you go, the faster and louder the tick tick tick tick.

Take this to a muffler shop now even if you have to use your credit card.

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+1, Carbon Monoxide can kill you without you realizing it until it’s too late. I can’t believe that’s the advice he would give you…

I would not trust or expect a muffler shop to replace warped exhaust manifolds and broken studs on this vehicle, this is for an experienced technician.

I trust my mechanic. Is this exhaust issue possibly causing the tapping/ticking sound? Maybe Ill try to record it…

Yes, leaking exhaust manifolds produce the tic-tic-tic sound from individual cylinders leaking. The sound is louder under load/during acceleration.

If your mechanic has a welder, show them this trick.

It could save them from having to remove the engine to remove the broken studs.


I uploaded a vid with the sound its making:

Jeeps have had an issue with cracked exhaust manifolds going back to the early 90s . The 4.0L engines used both welded and cast exhausts and both were prone to leaking at the 3-4 junction as I recall. Often the cast manifold would leak when cold started but as it heated it would swell and seal the leak.

I strongly recommend that you have a pro look at/listen to this. .The tapping sound could be minor, but if it turns to a rapping sound when you accelerate it by hand (under the hood) you may have a bad bearing. This would be cosistant

That sure sounds like an exhaust leak, that is what your mechanic plans to repair (warped manifolds/broken studs).

Its a disconcerting sound, thats for sure. I finally just drove over to my mechanic to ask him and he also said he believes its the exhaust leak he already identified. Ill be going back in a couple weeks for the repair.

Thanks everyone!