Looking for some help/guidance. My son has a 93 Honda Accord SE A/T sedan that we have had in the family for nine years. Car has about 250K in mileage on it and is in good shape for her age. Timing belt and water pump were changed at 185K.
Low oil pressure light comes on once car is warmed up. Below is what I have checked and done too this point.
- Oil has been checked and changed including filter ( this was prior to the issue)
- Checked wire going to sensor, no problems were noted.
- Replaced low pressure sensor and still have the same issue.
- Removed sensor and connected a oil pressure direct reading gauge with the following results. On startup oil pressure is reading 70 psi, but as engine starts warming up the pressure starts dropping and will go all the way down to zero if I let it.
- Engine is not making any unusually noise or knocks.

Everything points to the oil pump being bad and needs to be replaced. But I am looking for some guidance from people who have more experience with Honda's than I do.
Any and all help is welcomed.

 

I would say it is much more likely the main and/or rod bearings are showing signs of age versus the oil pump.

Another consideration is after market oil pressure sensors have been known to be faulty right out of the box; have you used a mechanical pressure gauge?

If it turns out to be a pressure issue which only shows up at idle when the engine is fully warmed up, I'd simply keep on driving the car until the engine quits (which could easily be another 100,000+ miles).

 

Did this problem occur after the last oil/filter change? If yes, suggest replacing filter to be sure an open bypass valve is not causing the problem.

Does engine knock (clanking) when started after oil change? If no, the rod/main bearing clearances should be OK. I've seen older engines knock pretty severely after an oil change and quiet down as soon as oil pressure is achieved.

Spec pressure is 10 psi min at idle and 50 psi min at 3k rpm. Does pressure rise as engine speed is increased? This could point to a oil filter bypass problem or less likely an oil pressure relief valve sticking open.

good luck

 

Thanks for the reply's.

Shipo - I do have a mechanical pressure gauge hookup. And the oil low pressure issue is not just a idle, once warmed up and pressure drops I increased the rpms on the engine and see no increase in pressure on the mechanical pressure gauge. Continues to go to zero.

TexasHonda - You are correct, the problem started after the filter and oil change. Engine sounds normal at start up and idling. And while watching the mechanical pressure gauge oil pressure does not increase with rpm increase after warmup. Oil pressure continues to drop to zero regardless of rpm. I shut the engine off once the reading goes below 10psi.
Did not even think of the oil filter, do you still think it could be the issue ? Never seen this before, but it is a cheap check.

Thanks for the help

 

As you say, easy to test whether oil filter is the problem.

Oil pump pressure relief valve is another possibility, but I've never heard of one failing.

good luck

 

Thanks for the help. Will be going by the Honda dealer to get a filter Tuesday and give it a shot. The current filter is a Fram.

 

TexasHonda,
You are the man. Changed the filter today with a Honda filter and you were correct. Bad filter. Started the engine, oil psi was 70psi cold once warmed up and radiator fan start running oil pressure was a steady 14psi at idle. Increased rpms and oil pressure increased with rpms. Still need to remove the mechanical pressure gauge and put the oil pressure switch in and give her a test drive. That will have to wait a day due to all the rain we are getting here. Never heard of a filter going bad much less a new one, but you taught me something new. Thanks


Mike

 

Good to hear of favorable resolution.

Never heard of oil filter failure before, but have examined the simple spring-loaded pressure relief valve by tearing apart an oil filter. It was likely assembled incorrectly.

good luck

 

Simple lesson is you pay for what you get. Years ago Honda stopped using Denso as their filter manufacturer and switch the Fram, but a filter built to Honda specs is not what is sold as an aftermarket part. I have Honda's with over 400k running and I still refuse to go aftermarket with such a simple item even though they are costly.

I always recommend to people that if they don't like the cost of a Honda filter, put one on, run it to the next oil change, drain the oil, replace the oil but not the filter. Thus every other oil change replace the filter. Seems to work out fine due to the quality, but I will always replace it if I am doing the job.

Awesome that everything seems to have worked out simple for you! Welcome to the HAF site!

 

Turtlehead,
Very true. Just in my 45 years of working on cars and as a retired navy aircraft mechanic have never seen or had a bad filter that was new. Live and learn. And the Honda filter was only 8 bucks. I think I paid that for the Fram extended guard filter.

Very happy it was such a cheap fix, instead of having to go into the motor. Was not looking forward to that.

And thanks for the welcome and the comment.