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justinsbg, ASE Certified Technician
Category: Honda
Satisfied Customers: 977
Experience:  ASE certified in Brakes, Electrical, HVAC, and Engine Performance. Currently a lead diagnostic Technician.
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I have a 2004 Honda civic LX that was overheating. I put in

Customer Question

Customer: I have a 2004 Honda civic LX that was overheating. I put in some head gasket sealant and it worked great for 10k ***** *****. I decided to replace the head gasket b/c it started to overheat again. I drove it to my garage and parked it. I did a combustion gas test on it and it tested positive. I disassembled and sent the head out to be checked. it was less than .002 warpage (good as new). I replaced the head gasket and now it wont start. Timing marks are on the money, I'm getting fuel b/c they are soaking the spark plugs. I' I'm getting spark b/c I took them out and they spark
JA: Thanks. Can you give me any more details about your issue?
Customer: I did a compression test and I have from cylinder 1-4... 120,170,120,70. Why?
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Customer: Yea my name isn't ***** ***** tho, its must be something the website gave me.
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Submitted: 1 year ago.
Category: Honda
Expert:  justinsbg replied 1 year ago.


My name is ***** ***** I would be happy to help. Can you please tell me if the check engine light is on? If so, what codes are stored?

Customer: replied 1 year ago.
p1457 that is an evap code that's been on for 3months that's unrelated
Expert:  justinsbg replied 1 year ago.

I have a few ideas here. Reminder, I have not been paid at this point and won't be until I receive a positive rating from you. At that point I will receive a portion of what you've already paid just Answer.

We replace a LOT of head gaskets on this model civic. The most common thing I see that guys miss is tightening G101 which is the main ECM ground. I would first make sure this ground is tight and clean. If it is let me know and we'll do some other things.

You can go ahead and rate me positively. Don't worry, there won't be additional charges for posting questions after you rate so we can keep chatting until the issue is resolved. Thanks

Customer: replied 1 year ago.
G101 is on the thermostat housing that is the braded copper ground or the other one that has the 2 grounds to the eye bolt? If so I cleaned and tightened it, plus I checked continuity to .1 ohms from the head to the frame. Only thing I was concerned with was that I didn't chase the threads with a tap before I installed the new head bolts, I did lubricate with oil, but certain bolts torqued different than others. the head may have not seated correctly against the head gasket. I followed torqueing pattern and the 3 torqueing intervals
Expert:  justinsbg replied 1 year ago.

It is on the thermostat housing. You can't really get to it without removing the air cleaner housing. If you are sure you tightened the head bolts to the proper torque, and you didn't hear any cracking while tightening them I wouldn't worry too much about that. The ground that runs to the frame is not the ground you need to check. G101 runs from the wire harness directly to the thermostat housing. It can easily be confused with the ground that runs from the frame to the thermostat housing, but that's not the correct one.

Customer: replied 1 year ago.
I cleaned that with sandpaper and reattached ground. This ground still wouldn't cause low compression though. Only two of the bolts sounded like they were going in dry and they were making a "tink" noise when torqueing. I cleaned both the head and the block with scotchbrite and it is 95% clean. Compression is 120, 170, 120, 70, so 3 cylinders are below the minimum of 128. It ran great before this, what changed?
Customer: replied 1 year ago.
would that low of compression cause it not to start?
Expert:  justinsbg replied 1 year ago.

It would probably start, but just run rough. Is the green key light blinking on the dash while cranking?

Customer: replied 1 year ago.
Ill have to check tomorrow when I get to the garage. I'll be in touch, thanks so far.
Expert:  justinsbg replied 1 year ago.

No problem. I will look for your response

Customer: replied 1 year ago.
Just to let you know I ended up taking the whole thing apart, retapped my threads on my block and put back together. I remembered 2 bolts felt strange when torqueing and my head gasket might have not seated correctly. Compression greatly improved and started right up. Figure that would be some great info to pass on to other users.
Expert:  justinsbg replied 1 year ago.

Good deal. Hey, if your happy with my response time and customer service please rate me positively. If you need additional information about anything else with this vehicle let me know.

Expert:  justinsbg replied 1 year ago.

Good deal. Hey, if your happy with my response time and customer service please rate me positively. If you need additional information about anything else with this vehicle let me know.