When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I am slowly progressing with this project. I was able to separate the old manifold upper and lower today. However, to get the nuts off the studs which hold the upper to the lower I had to grind through them and the studs. Does anybody have a place to get the part number for these?
I was finally able to finish the intake replacement two weeks ago. I replaced the starter at the same time, and fixed the throttle cable.
When she started for the first time in a while it was hard cranking but then she went. However, after a 5-10 minute idle, I tried to drive around the block and temps soared (247F). I was having an overheating problem before this intake change, but never to this degree, .
I was struggling to diagnose it before my intake/idle issue appeared. Here are the symptoms as I remember them:
1. Typically it only overheated at idle. Turning the heat up helped cool the engine.
2. I couldn't get the cooling fans to turn on. Jumping the switch with a paperclip turned them on so I know it isn't the fans or relays. I replaced the switch and it didn't get the fans to turn on. I also continuity tested both switches in hot water on the stove with a multimeter.
3. The coolant has boiled over in the past out of the overflow tank and it was sludgy and foaming.
Diagnoses I have considered before:
1. Bad water pump.
I didn't go further on this since I had the valve cover off last year to replace the cam position sensor. I did a valve lash adjustment at the time, along with spark plugs. While in there I noticed the timing belt looked new so I assumed it was, and typically when you do a timing belt on these you do the water pump with it.
2. Bad thermostat.
I don't know how this would cause my issue. Usually they fail open so I would have an underheating problem.
3. Head Gasket.
Since the fan switch wasn't working, and the switch is right by the thermostat, which is also a high-ish point in the water jacket, I thought that exhaust gases were passing into the water jacket and getting stuck at the thermostat not allowing the temp to get high enough and turn on the switch. I did an exhaust gas test at the radiator with some of that liquid detector stuff. It came up negative.
I am at a loss here on how to proceed. Is there an easy way to test the water pump? I don't want to pull the head after all the hassle of the intake, so that is my last resort.
So if I am going to get all in here I plan to do a few things simultaneously.
1: Head gasket
a. the gasket itself
b. head bolts? I don't know if they are reusable on this engine
c. valve cover gasket
d. belt side cam seal
2. Timing belt
a. crank main seal
b. water pump
c. tensioner pulley (is this a common failure point / worth the replacement cost?)
3. Driver side motor mount (already have it, purchased a while back and never got around to it)
Are there any other things I should replace along the way or things to consider that I might get hung up on. She has a decent oil leak so I suspect the seals are bad. I replaced the cam end cap on the other side already.
"Marge, anyone could miss Canada! All tucked away down there."
Joined: Feb 2016
Posts: 9,641
Likes: 1,283
From: Barrie, ON Canada
Rep Power: 222
Re: 04 Civic DX, Manual Trans Idle Issues
The head bolts are reusable, which is why these cars have issues because they don't clamp enough. Could look into different bolts. And definitely get the head checked
Been looking for parts. While I do, 2 questions arise.
1. I noticed the tensioner pulley is expensive compared to the rest of the items. Is this typically something that goes on these engines?
2. How difficult is it to do the crankshaft main seal? I have been chasing an oil leak for some time and it might be a good idea to replace it while in there.
So I got most of the parts in over this week. I dug into her this weekend. I found a few things that explain some other things.
1. Oil pan is totally coated. I suspect the oil pan gasket was leaking in multiple places.
2. When cleaning up the pan I used a wire brush for the rust and found 2 slightly larger than pin holes in the pan. So that explains at least some of the leak.
3. Removing the timing cover I saw no oil around the cam sprocket so I suspect that seal is good. Is there any reason to replace the seal for age reasons if no leak is seen?
4. The belt says honda on it so I suspect original belt, no cracks in it on the top or bottom side, but does show it's age. I think it has never been done. Alternator and PS belts look similar.
5. After removing the harmonic balancer I found a bunch of oil near the bottom of the timing cover. I had been spraying penetrant so its possible that I made it look worse than it is. Either way, I think that either there was a leak in the pan gasket right there, or the crank seal is leaking, or the oil pump o-rings are leaking, or a combination of the 3. I plan to do all 3 anyway.
6. The water pump and tensioner pulleys feel solid but I bought them so I will change them out. At this point I will wait until I get the head off and on to do them.
7. I messed up the timing when removing the harmonic balancer. Afterward, I set the crank to TDC. I just need to turn the cam sprocket until it lines up properly before putting the new belt on. I will check the firing order, but I think I just need to ensure that both cylinder 1 valves are closed and both cylinder 3 valves are open and the timing will be correct. Any reason that this method won't work?
8. I found many specialty bolts quite rusted and rounded off that I will need to order before reassembly.
9. The adjuster screw is missing from the alternator bracket entirely. I guess whomever put it in just got the belt tight by hand.
Its not going too badly I think. I haven't broken a bolt off yet.
Coolant shows signs of boiling and bubbly nature in the water jacket just like at the thermostat. I also got a bunch of gunky coagulated coolant out of the drain plug hole, next to the oil filter. I am not sure how to look for signs of gasket failure on these MLS gaskets.
It looks like the cylinder 1 head, right, is cleaner than the rest at the top and bottom. Also looking at the pistons themselves, cylinder 1 is cleaner than the rest. I think that's where my leak was.
Over the past 2 months I have put everything back together. Today I finally filled the oil pan and cooling system and started her up. She started relatively easily considering how long she has been sitting. I had removed the thermostat and only filled the system with pure distilled water to allow for it to flush the heater core since that was the only part of the cooling system I didn't clean by hand. I saw no oil or coolant leaks under the car during running or shortly after.
However, to my dismay the radiator fans never turned on. The shop manual says that the switch on temperature is 196-203 F. I tracked the ECT sensor to 208 F before I turned off the car (Don't want to boil the water). Additionally the paperclip jumper still turns the fans on just fine.
I am at a bit of a loss here. The only thing I can think of is that the ECT sensor is reporting the wrong temp and she never actually got to 208. The part is new and NTK so I trust the part. The actual switch sensor is FACET brand, which I don't know much about, but it did test good for continuity when I placed both it and the original in boiling water.
After some reading of the service manual I learned some things which made me decide to proceed and I am glad I did.
1. The ECT sensor, while externally very close to the fan switch, is measuring coolant temp at a hotter spot in the water jacket than the fan switch. I don't know why this didn't occur to me earlier but here we are.
2. The service manual also states that normal engine operation occurs between 176-212 F.
From these two pieces of info I figured that by only allowing the ECT sensor reading to only reach 208F I was likely not letting the fan switch get to operating temp. So since I wanted to test this, I started flushing the system getting ready to add coolant and be more comfortable hitting those higher temps. During my water only flushes I would get her up to 200F then let the car idle for 5 minutes, before draining and repeating. The radiator only drains about 2 quarts anyway which is half the capacity so this would be iterative anyway. During one of those cycles I let her idle a bit longer and I heard the fans come on, so it seems like I've been successful!
I am now doing a final flush and then adding concentrate to hope for close to 50/50 mix. I'll dial that in in the coming days if she remains a driver.
. 
