Bugman1400

My 1998 Civic LX seems to have an intermittent problem with the engine shuddering while driving. It does not have a problem at idle or while accelerating. And, it never cuts off but, the shuddering makes me inherently lift my foot of the gas pedal. The shuddering then stops and the car acts normal when I put my foot back on the gas again. I have not received any CELs during this. I also do not have any overheating or A/C issues.

Wankenstein

Googs: https://www.google.com/#q=intermitte...+while+driving

Bugman1400

I think those issues are related to tire balance or alignment issues. Perhaps the term "shudder" may not be correct. I've seen that term refer to clutch problems. The problem I have with my '98 LX, is not a tire balance, alignment, or clutch issue. It seems to be engine related and occurs at different speeds. My first thought was that it was a TPS issue but, I still haven't seen a CEL. So, then I thought it may be related to the fuel delivery system. I could also see it be a problem with the A/C. If the A/C compressor was, for some reason, causing a temporary severe load on the engine, it may cause the engine to bog down. That is what it feels like most...is that the engine is bogging down from either excessive load, misfiring, or insufficient fuel. However, I would have assumed that anything internal to the engine or fuel delivery would have caused a CEL.

ezone

No, not true. The computer is not the all-knowing, all-seeing mystery box people want it to be.

Same goes for a code reader or a high dollar scanner....they are only tools that supply some information, they don't give all the answers.
In the hands of a master, they can be invaluable.
In the hands of someone else, sometimes they may as well be a wheel stop.

There's a whole bunch of problems a computer cannot 'see', cannot detect, does not monitor, and/or was never programmed to do (partly because the engineers couldn't ever predict all the different ways any little wired thing could possibly fail). There's more reasons, but I'll stop.

Wankenstein

Read the third hit I linked previously in Google search:

(copy and pasted) "A shudder or vibration may develop while driving at speeds between 35 and 40 MPH. Our technicians tell us this condition is commonly caused by a failed automatic transmission torque converter. It is recommend to replace the torque converter and install an updated powertrain control module (PCM) to correct this concern."

You didn't list your transmission type and I haven't seen or read much related to differential issues + Civics so, may have no correlation to your car's issue.

Bugman1400

A failing or aging torque converter is one of the things I initially suspected. The wifey just got back from the dealer after the routine oil change with the diagnosis. If I had taken the effort to check any fluid levels, I would have noticed missing radiator fluid and oil. That evidence points to a troubled head gasket. The quote to replace it was for $1000 which includes both labor and materials. While I think that price is fair, the engine seems to easy to work on as not to take the weekend to perform the work myself. However, after reading Turd's breakdown of how his head had to be milled, I'm a bit hesitant to dive in. I took a look in the DIY section of this forum and did not see one for head gasket replacement. Any suggestions would great.

Wankenstein

If you suspect a head gasket leak then do a cold pressure test on it to rule out any external leaks. Do a block test on it to find out if there's exhaust emmisions getting into the coolant. If it turns out to be a head gasket breach and the engine has not overheated then the cylinder head may not be warped and may not need resurfacing. Can check head with a metal straight edge and feeler gauges (search youtube).

My HG replacement cost around $500 altogether including machine shop, OEM parts, helicoil kit (repaired stripped block bolt hole) and fluid replacement.

Bugman1400

The engine has never overheated, however, I would expect to have to do some milling since a gap between the block and the head is quite often the reason the gasket has failed in the first place. How much did it cost for you to mill? Did you check it before and after? Do you remember what the gap was? Did you overheat yours?

ezone

You pull the head off and have it measured for flatness by a machinist or someone with a precision straightedge.
If it never got hot, chances are good the head is still measuring flat and will be serviceable as-is.

Head gasket failure can easily be the root cause, they fail first in many cases.

Bugman1400

I figured I would post the final diagnosis of this issue. The problem was a head gasket compounded by worn out piston rings. I had the head gasket replaced at my local dealer who also milled the head. Unfortunately, after the engine was put back together, the mechanic could never get the engine to start. He then performed a compression and leak down test and found the issue with the piston rings. He also tried to blame the crappy compression on the head and said the head needed to be rebuilt. My guess is that the new head gasket and newly milled head had not had a chance to seal together which is usually done after the engine heats up a few times. Anywho, after the wife and I complained to the manager, we got nowhere on the now dead car. My wife then followed up with a detailed complaint to the BBB. We got a call the next day from the manager who had read the complaint already. He then said he would fix the car if we would resolve the complaint. The manager then had the rings replaced and honed the cylinders. Everything works great now!

Wankenstein

Whoever did the headgasket should have performed a dry and wet compression test and a leakdown test before removing the head to isolate a bad cylinder(s). Sadly, some mechanics don't do a proper dry/wet compression test and leakdown and just either assume it's the head gasket causing compression loss or they just want to get paid regardless knowing that a headgasket may not be reason for compression loss. Unless I am mistaken, a compression leak via headgasket involves two adjacent cylinders.

Wankenstein

$60

I checked the head and block after removing the head. I didn't check it after because I could see it was milled and the machinist is very good at his occupation.

Block was under .002 and head had spots over .004

Yes.