I have a 1998 Civic sedan 5 speed that I have named “The Rumbler.” It has this very peculiar behavior - the only way to describe it is that the engine rumbles when I’m starting in 1st gear, and also a bit when first entering 2nd gear…sometimes a very little bit when going into 4th gear. In order to keep it smooth enough to tolerate, I am forced to give it more gas than necessary and also to hold down the clutch longer than normal.
But what is peculiar is that this situation is variable.
I only have this effect when:
It’s very cold out and the car has only been on for up to ten-fifteen minutes. That is to say once it’s warmed up, this issue goes away…for a while…
Because the next time it happens is after the car has been running for a good while, say about twenty minutes. That is how it comes about on mild and warm days, or how it returns again on cold days. And it will remain in this “rumble mode” for the entire time I am driving it.
So to recap - if it’s cold, it starts out as The Rumbler, relaxes back to normal for a few minutes, and then becomes The Rumbler again from having been on.
If it’s warm, it starts off normal and then becomes The Rumbler after twenty minutes or so.
I would describe the rumbling as a very strong vibration that can shake the entire car rather violently if I am not feeding it more gas than usual and holding the clutch longer than usual.
The car has been doing this since I got it in 2007 with 90k. I have put 40k on it in this time, and it still runs strongly. I have kept up with tune ups, oil changes, etc. I simply have never reported this problem to my mechanics because I fear it will end up being some amazingly expensive issue that they may not even fix properly. I figure that since the thing keeps going and gets me everywhere I need to go, there is no sense taking risks with money until I know what could be causing the problem.
Some more points:
There is no noticeable change in the smoothness of the engine when it’s not engaged to the trans. ie - revving while in neutral doesn’t produce the rumbling.
Once it kicks in, rumble mode is continuous for the entire time I am driving the car - but isn’t abated by simply turning the car off and turning it on again. It only goes away when the car has been turned off and parked for a few hours.
This leads to me assume it’s something heat related.
Correction - I meant 3rd gear, 4th gear.
Also want to add that my car isn’t overheating. The temp never goes past the normal midway point.
There is no smell associated with it. No burning, rotten eggs, etc.
Let me make sure I’m reading this right:
It rumbles, but it ONLY rumbles when you’re shifting into 1st or 2nd gear, and sometimes 4th?
If so, I suspect your clutch is chattering. Two general causes for this: Fluid leaking into the clutch (generally indicates a problem with your engine) or worn clutch components. I suspect the latter, but don’t rule out the former.
You didn’t mention having the clutch changed before this started to happen, but if you did, it can also be caused if the person who put the clutch in got grease or oil on the wrong parts of the clutch.
I mistyped - I meant a little into 3rd, by 4th and 5th gears it’s smooth enough to feel okay and I’m not forced to hold the gas and clutch longer than normal.
The only thing the clutch has needed was a new hydraulic two years ago. Mechanic said that everything else (plate, etc) was fine at the time of that repair.
Same diagnosis.
Did the problem start after the new “hydraulic” two years ago?
No, the problem has been with me since the day I got the car. While not familiar with the connection between clutch and engine, I am hesitant to assume it’s clutch related because it seems to be so dependent upon the engine temperature and not at all related to how much or how little the clutch has been engaged during the driving session.
Unless you were very unclear, I don’t see that it’s all that temperature dependent.
You said it does it when the car is cold, and when the car is warm. Since it does it through all normally-seen temperature ranges, it’s probably not a heat issue.
Worn clutch components can cause intermittent chattering.
It happens when the car is very cold, stops happening when it is slightly warm, then starts up again after the car has been on for a while - to me that means that it is only happening when very cold or at the highest normal operating temperature.
Like I said, I don’t know much about clutch-engine issues so I’m not naysaying a clutch problem. But it’s not an intermittent issue. It’s not random. I know for sure when to expect it, and it doesn’t go away and come back without this established causality which has to do with whether the car is running very cold or very warm.
Recap - on a cold day (<40 f) it starts in rumble mode and remains there until the car warms up a bit, then returns when it’s at full operating temperature.
On a warm day, it starts normal and becomes The Rumbler once it reaches full operating temperature.