I just recently acquired a 1999 Honda Accord EX 2.3L (4cyl) with a manual transmission. This thing is in immaculate shape, no rust, no dents. The previous and only owner kept records of every service written down in the owners manual.

I got the car at 175K miles. Being that it is a Honda and in such great shape I didn't think anything of it.

Fast forward another 3K miles to when I was going to change the oil again and top up any fluids that it needed (it didn't need any fluids added last time, but you check just the same).

So, after driving around for the day, about 50 miles around town, just errands and what not, I go to move the car in the driveway to put it on the ramps to do the oil change. When I move it, I notice for the first time, a few dots of oil under where the car is normally parked. This is INSTANTLY something, because for the last 3K miles, there has not been a single dot of oil on the driveway.

I climb under the car and see that no oil is coming from anywhere you might expect. There isn't even any wet spots.... except, for over on the A-arm and drag linkage. Very strange, I now look in the engine bay above where that all is. Found the leak, the coolant reservoir. Which a week ago, was happy sitting half full with green fluid, is now overflowing with a thick brown sludge. https://prnt.sc/fpp2uo (picture of reservoir) So I pop open the radiator cap to look in there too. https://prnt.sc/fpp2ts (same stuff)

Now I am thinking blow head gasket, somehow. I never drive this thing hard, so it seems unlikely. I have been checking it pretty regularly for fluid issues, as it is a new to me car, so I know this issue has happened sometime within the past few days (5 at most).

I go ahead with the oil change anyway. https://prnt.sc/fpp3nx Now I am really stumped. Any head gasket I have ever seen, there is some oil in the coolant, but mostly it is coolant in the oil. As you can see, there isn't a single drop.

Drain the radiator and flush it with water. https://prnt.sc/fpp3ik

I do online research, and read that it could be an oil cooler o-ring, but I don't have an auto, come here and see that everyone is saying head gasket. So what is the issue? Is it a head gasket? Is there an oil cooler even on a manual, that it could be, because that would be a LOT less work for me in the driveway.

Also, so much for my bullet proof Honda theory.


P.s. It should be noted that the car has never exhibited a higher than normal heat. It has never in my 3K miles of experience come anywhere near overheating.

 

If this is in fact a head gasket issue, a cylinder leak down test should confirm it.

 

I also say head gasket, but the o ring thing is for sure worth taking a look at first. If it were me, (I enjoy solving problems with cars) I would check that, even replace it. oil change it, drain the water, and put new stuff in. Drive it around, if the same thing happens, well your best bet is a head gasket. Im by no means a expert, but I do have some personal experiences like this so yeah. Prolly not what you wanted to hear, but the above comment will tell you if its a head gasket or not, o ring just sounds cheaper to look into first.

 

Any recent work on your car that you may have left out?

Not sure what you mean by a-arm and drag linkage? Is that the lower control arm and the sway bar linkage? If yes, what side of the engine did you find oil? Posting a picture may help.

I can't think of anywhere else where engine oil can mix with coolant other than the head gasket.

I'd suggest renting a radiator pressure tester from the parts store. Attach the tester to the radiator neck and put 15-16 psi on a full radiator. Pull the spark plugs to see if one of the cylinders is getting coolant inside? Maybe there is another component where the coolant can mix with the engine oil that pressurizing the system will reveal?

Is there any chance you added the wrong fluid to the radiator? I know it's a long-shot, but had to ask.

Typically an overheating condition would cause the head to warp and the head gasket would not seal causing your problem. Did you have any overheating problems?

You may want to fill everything up and see if the problem returns.

 

No work on the car since I have owned it, only the past 3K miles. There is no indication in the book that anything has been done aside from routine maintenance.

I did include pictures of where I found the oil leaking from, but none from under the car. It was all over the passenger side a-arm/control arm, and linkage assembly there. So, I looked above it, since that is no where near where I would expect, because there is no engine over that particular area.

This car is new to me, so I am not familiar with its history, other then what was written in the owners manual from the previous owner. Talking to the man's wife, it didn't seem like anything out of the ordinary ever happened with the car.

I am on vacation now though, so any further investigation must wait. I will be sure to update this thread with my findings, be it good, bad, or inconclusive.

Thank you all for your input so far. I will do a leak test/pressure test when I can.

 

I just went and did a JDM engine swap to a similar f23a.






New to me Block, Heads, Intake manifold, Altinator.
Reused old throttle body and vtec valve, because the sensors could not be swapped.