93 CX, cooling problem?

[tucsonron]

'93 Civic CX. 175k miles. I am not driving it at all because of these problems.

When the engine heats up the valves start clattering.

Does it ever happen that the head fails to get lubricated, or get coolant?

Also, the fan never kicks on, ever...

It is running rich, that's for sure. The spark plugs are fouled black with carbon deposits with very little use. I think the computer never goes out of warmup mode, and continues to set a rich mixture.

Is there any way to force a lean mixture on a CX (just to see what happens, diagnostically)?

The Coolant Temperature Sending Unit works, but it never raises above a certain temperature. The thermostat is fine. I think, perhaps that coolant isn't getting to the top of the block. Or, perhaps the CTSU is shot. I don't have a batch of CIVIC CX CTSU's to compare it to! So, I don't know what a "good one" does or how they fail.

I have no way of knowing how to diagnose the CTSU or the water pump.

The books all say, "Listen to the water pump, if it's 'whirring' it's busted." Well, it just so happens that I don't listen to Civic Water Pumps every day. So, I don't know what a failed water pump sounds like. It's not leaking, though.

Can anyone think of anything I might check. I hate having this car sit in the driveway for weeks.

[GasSavers_Erik]

It could be just that the cooling fan isn't coming on (bad cooling fan relay or temp sensor). If you have AC turn, it on and that should force the cooling fan to turn on and see if it still overheats.

Both problems (rich and overheat) could be by an air bubble in the top of the block- look for an air bleed screw at the highest point.

[tucsonron]

Thanks for the reply Erik. I certainly never thought to look for an air bleed screw. The fan motor is fine, and the relay is fine. Right now, when I drive it for more than five minutes, I always turn the fan on manually (with a thick wire bypass in the relay box). Even with the fan operating, it seems like the head os getting hot (valve clatter and there seems to be some knocking).

I will seek out the air bleeder valve. Thank you!

[civic94]

did you adjust your valves? try posting this in honda-tech.com, I use that alot becuase there are lots of actual Honda-Techs on that site, the only con is that they are not that nice, and are more geared towards swaps, turbos, more power and performance instead of economy.

[GasSavers_Erik]

On the Accord of about the same vintage, the air bleed screw is located on the cylinder head very near where the upper rad hose attaches.

[tucsonron]

Thanks, civic 94. I have tried other forums in the past with problems. There seem to be two types of responses... 1) Yo, dawg! Get rid o' dat d15b8 and drop in a B series, yo... That kind of response comes from the 20 year olds who do quite well for themselves (their cars are impressive, and so is their knowledge). After repeatedly emphasizing that I am going for fuel economy and not speed, they are dumbfounded... unable to comprehend that I am not looking to drive off the highway at 120 mph and be memorialized by giant "RIP 1988-2009" sticker on my girlfriends decaying Hyandai.

Then there's 2) "I know exactly what the problem is, and you should too. I am not going to tell you. You should take the car to a mechanic, dumbass" This comes from the 50 year old Honda tech guys who used to be the 20 year old guys in 1... but somehow managed not to drive off the highway at 120 mph. These guys have seen everything 500 times, and can't comprehend that other people haven't... These guys are completely right as well. I SHOULD "just take it to a mechanic", but I want to learn as much as have it fixed. I wish there were "teacher mechanics". Like, a place that can do diagnostics, and say... "You need to put in a new head gasket" and then I could put in the head gasket, take it back and they would CHECK on it.

There are all kinds of things that can be "half-wrong". Like... on brakes, if the return springs are old, the brakes will work, but the pads will wear out TEN TIMES FASTER. How do you know if the return springs are worn? It's easy, IF YOU'VE SEEN THEM 5000 TIMES. If you haven't, there's no way of telling. So, you do everything perfect, and still need to get new pads every six months. All I need is Guy #2 to LOOK AT the spring and say, "Spring's shot..." but Guy #2 never says, "spring's shot..." he looks at and thinks, "The spring is CLEARLY shot, how does this idiot not see that?" and then says, "Listen, you don't know what you're doing, just have your brakes done, and save yourself the aggravation."

Oops! wrote a novel... In short, I am hesitant to ask on hondatech or hondaswap.

Erik - I will do a bleed today. After you mentioned I remember bleeding a radiator somewhere, but I am not sure it was this car. I sure hope that's it. If it solves the problem, you will have great thanks!

[R.I.D.E.]

Check your coolant recovery bottle, where the coolant is not under pressure.
The level should rise as the engine heats up and drop when it cools down. It is located where the small hose just below the radiator cap goes to a translucent plastic jug, with a snap off cap.

It has a hot and cold level (if memory serves me) and you do not have to open it to see the level of the coolant in the jug.

If your engine has an air pocket in the cooling system and needs bleeding, in my experience, the recovery jug level will not rise (when getting hot) or fall (when cooling off).

If the level doesnt really change then you should bleed the system. If you have already bled the system then you know it's working right when the hot coolant expands and increases the level in the jug, and when cooling down the level in the jug decreases.

If you get that working and you have to add fluid to the recovery jug more than once, you probably have coolant loss somewhere, and if you do not see any leakage on the ground, there is a good chance it is the head gasket.

Cars with blown head gaskets have a very different exhaust smell. It's so unique I can smell it when driving down the road behind a car with a bad head gasket.

A serious air pocket could be the cause of the valve noise you hear when the engine is hot.

Mechanic for almost 30 years.

Hope this helps.

regards
gary

[R.I.D.E.]

If you have an air pocket in the coolant system it will end up at the highest point which is usually the head.

I am pretty sure the bleeder nipple is located where the bottom radiator hose connects to the engine. Bleed it until no more air comes out. It should be a 10MM (might be 12) size and look like a nipple with a threaded base, with a small opening in the nipple. Turn it counter clockwise to bleed the system. You should do this with the radiator cap off, and keep the radiator full as you bleed it, starting with the engine cold.

Another thing to check when the engine is running. The top radiator hose should get hot if coolant is flowing and the thermostat is working properly. The bottom radiator hose should be about 60 degrees cooler. You can easily feel the difference by touching the two hoses with your hand.

If the coolant is low the sensor will not read the temperature correctly, and that COULD be the reason why your plugs are black. The computer relies on the temperature signal to control the mixture. The black plugs could also be due to repeated cold starts while you are trying to figure out what the problem is with the cooling system.

regards
gary

[R.I.D.E.]

Be very careful is you engine is getting very hot, you could have a blast of air and coolant come out of the radiator with the cap off.

You can also watch the coolant in the top of the radiator for air bubbles. If they have steam it is probably the head gasket. If the thermostat is working when it opens you can see the coolant start to move through the radiator with the cap off.

Do not UNDER ANY CIRCUMSTANCES, keep any part of your face or body over the radiator opening when you are doing this, the super heated air in the pocket could burn you very badly.

regards
gary

[tucsonron]

Gary - Thank you for the thorough advice. The bleedout procedure is...

1) take off the radiator cap.
2) Start the engine
3) wait for the engine to heat up
4) when coolant comes out of the bleeder valve close it.
5) Engine off

?

Won't the coolant overflow almost immediately?

If the system is bled, and there is low flow, would that indicate a water pump problem?

There is probably not a head gasket problem, I just did a compression check and the compression was even and high across all four cylinders (Phew!) Also, I recognize the stink of singed ethylene glycol from past blown engines (actually had a connecting rod shear on an 11.0:1 Chevy 350 once! KLANG!) That sweet smell of a dead engine!

I am thinking it is a bizarre problem is the CTSU now... Nothing really adds up anywhere. It seems like everything and nothing is broken. And I don't know how to diagnose the water pump. The guide said to check for leaks (It's definitely not leaking). I am not losing coolant anywhere. It also said to use a mechanics stethoscope to listen for a "whirring" sound. I know one thing for sure... I will hear whirring and whooshing, but with nothing to compare it to, it won't mean anything to me... It's one of those things you "just have to know".

Now that I've looked back through my notes, I see that I suspected the oil pump was shot as well (I did an oil change and there was NOTHING in the oil filter... dry as a bone). So... so many little goofy problems, I don't know where to start. I just hope I can change the oil pump without taking the engine out.