91 Honda Civic Si (1.6L) head gasket?

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Own a 1991 Honda Civic Si 3dr Hatchback that may possibly need a new head.

I bought this car brand new in Oct 1990 and drove it to 515k miles until it just died on me while driving on the freeway.

I drove with bad valve stem seals and with a disconnected temp gauge switch for years. Finally caught up to me. The car over heated
There are traces of a milky substance on the underside of the oil cap

The car starts up fine without any hesitation.
The fan does turn on now when leaving the engine running for a while.

I have yet to pull the thermostat to see its condition

Not sure where to start
I do know that the car needed the valve steam seals replaced prior to it dying on me. I was getting blue smoke at idle.

Is there a chance that the thermostat just got stuck and maybe, just maybe, the head gasket is fine and all it needs is some attention.
I have no check engine lights and car starts up fine. Again, the oil cap does have minor traces of a milky like substance but I'm no expert.

If the head gasket was blown then what should I do next?

Can anyone here provide me with the Do's and Dont's when removing the head?

If head needs to be repaired I want to remove the head and take it in to a shop for the repair.
I will be removing it and reinstalling it

What is expected of the repair shop as far as what should be done to the head, what gets repaired and what gets replaced?

I have no experience with this type of engine work but I want to tackle it myself.
Just need to know what things to watch out for.

I almost junked the car the other day and I stopped for a second and told myself that I would give the car another chance.

Any advice is greatly appreciated.
 
Is the radiator staying full? With the engine cold, take off the radiator cap start the engine with the cap off and rev it, there should not be bubbling or stuff blowing out of the radiator.
 
The head gasket may or may not be blown. I'd hate to spend money getting the head rebuilt when the rest of the engine could be two oil changes away from needing rebuilt.
 
Remove the head and you will have your answer. With over half a million miles, I would say that Honda has served you very well.
 
IF the water pump hasn't been replaced in half a million miles, it could be just worn out and not circulating as much coolant as it could be. The milky stuff on the oil cap could be from short trip usage. You can get a rebuilt head for 300 bucks on eBay if you decide to go that way
 
Valve job/replacement head and by default you'll get a new head gasket
wink.gif
 
Put a used engine in it. You have no idea what the lower bearing clearances are and they could be 9/10 of the way out from age anyway. Antifreeze contamination would finish it off.

IDK if you have a single or dual overhead cam but it can go from easy to tricky getting at the valve seals. Doing these is way easier than pulling the head, but if you pull the head, you don't have to mess around with holding the valves from dropping into the engine.

Do you have time for a science experiment or is this your only car and only way to work?
 
I just can't see the effort and expense of rebuilding an engine for a 26 year old Honda with over 500k miles. That car has got to be worn out.

I'd be shopping for a replacement.
 
Anyone know how many miles the bottom end can get?
These cars are solid and engines on the accords have easily gone 600k without any work.
 
Originally Posted By: 55Test
IF the water pump hasn't been replaced in half a million miles, it could be just worn out and not circulating as much coolant as it could be. The milky stuff on the oil cap could be from short trip usage. You can get a rebuilt head for 300 bucks on eBay if you decide to go that way


Replaced the original thermostat at 380k. Water pump was always replaced when I would do the timing belt
 
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Do a compression test before spending a dime. While the plugs are out,check them for coolant. Please report back. What does the dip stick look like?
 
What's the rest of the car like? Is it worth fixing?

I think though this has to pass emissions in your state, and it's pre-OBDII, so I'm not sure how that weighs in... if it's easier or harder to pass the testing. Up here it'd be worth fixing, assuming it wasn't rusted away (extremely unlikely!), by virtue of being pre-OBDII and easier to pass inspection.
 
Originally Posted By: eljefino
Put a used engine in it. You have no idea what the lower bearing clearances are and they could be 9/10 of the way out from age anyway. Antifreeze contamination would finish it off.

IDK if you have a single or dual overhead cam but it can go from easy to tricky getting at the valve seals. Doing these is way easier than pulling the head, but if you pull the head, you don't have to mess around with holding the valves from dropping into the engine.

Do you have time for a science experiment or is this your only car and only way to work?


Car is not in use at this time
 
Originally Posted By: supton
What's the rest of the car like? Is it worth fixing?

I think though this has to pass emissions in your state, and it's pre-OBDII, so I'm not sure how that weighs in... if it's easier or harder to pass the testing. Up here it'd be worth fixing, assuming it wasn't rusted away (extremely unlikely!), by virtue of being pre-OBDII and easier to pass inspection.


Passed the last smog back in 2015
 
A half a million mile engine that got hot on the highway? Replace it or the car depending on the car's overall condition.
 
IF you have the ability to do the work yourself, then it may be worth attempting either a HG replacement or engine rebuild. But lets face it. With 500k miles, other things WILL fail. Axles, transmission, wheel bearings, brake calipers.

I do have several beater cars, but not with that high of a mileage. Once you throw some money at one problem , you will be inclined to throw more at the next because you already spent xx amount on it already. It does not sound like you have the ability to rebuild the engine your self.

Originally Posted By: Gito


I almost junked the car the other day and I stopped for a second and told myself that I would give the car another chance.

Any advice is greatly appreciated.


It's a machine, not a person so it either is economical to repair or it is not, it does not get chances.
 
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Originally Posted By: eljefino
Put a used engine in it. You have no idea what the lower bearing clearances are and they could be 9/10 of the way out from age anyway. Antifreeze contamination would finish it off.


+1
This would be the most economically efficient way of putting this car back into use.
Yeah, you can try removing the thermostat just to see what happens. You can also probably drive the car for some time with the pressure cap left loose and venting any pressure to the atmosphere. You won't being doing any harm either way since any damage is already done.
If you overheated this alloy engine to the point that it actually stopped running, though, you're likely to have to have the head and maybe the block deck milled flat at the very least not to mention that you may have cracks in the head. Alloy engines don't take kindly to serious overheating.
Mayo inside the fill cap on a Cali car is not a good sign.
 
Decided to take my civic for a drive, this after my car over heated a while back and left me stranded on the freeway for the first time. Drove on the freeway at 70 mph to a store 10 miles away. Drive back at 80 mph most of the drive and the car never over heated. Car feels great and has a lot of power.
 
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