boostincoupe

Here's some background info. on the car:

- 1997 civic EX coupe, 114k
- Bought with 73k in April 2001
- Not-a-one problem until now
- Oil changed regularly
- Haven't touched the coolant since I got the car
- Timing belt replaced, water pump "said" to be fine by mechanic (not sure though)

Here are some symptoms I've documented:

- The car is taking longer and longer to warm up; first the temp. gauge gets to normal operating temp. , then the heater kicks in about 1-2 minutes later. VERY annoying in 10 degree Minnesota winter weather.

- After about 10 minutes of driving, the temp. gauge starts to creep up from 1/3, where it has been since I've owned it for the last 2.5 yrs., to about 1/2 way then all the way up to just below the H in some cases, before it drops abruptly down to about 1/2 way. Then it'll do it all over again after about 5 min. at normal operating temp.

- The temp. level goes back to about 1/2 or even 1/3 when I put the heater on full blast for about 30 seconds or so. Then the ******* thing just does it again after about 5-10 min.

- I have checked my oil, it is not milky at all. No signs of coolant in my oil, or oil in my coolant (i.e. overflow tank).

- When it first started to overheat, I pulled over and popped my hood. The coolant was JUST above the MAX level, and yet the temp. was consistently at roughly 3/4 level.

- Now, after about a week or two, when it happened again (didn't happen in between that time), I noticed the coolant level in the overflow tank was below the min., however there was no sign of any coolant in my engine bay or on any parts that I could see. But I'm not really sure what it would look like all over the engine bay, green I assume? If so, then I didn't see any.

- My plugs look normal.

- When the overheating issue occurred and I had a chance to pop my hood (usually I'm in a rush to get to my class so I can't always check it), I check the upper hose, which is immediately hot to the touch, whereas the lower hose is relatively cold. Not freezing, I can feel the warmth, but nowhere near the upper hose.

- I haven't noticed any leaks in my driveway, but then again, I haven't really been under my car since the snow fell about a month ago.

- There are no signs of white smoke coming from my exhaust, either at idle or WOT when boosting.

- I have NOT opened the radiator cap, because I constantly forget to before I drive the car, so it's too hot to touch then . Is there a certain level that I'm supposed to gauge it by on the radiator?

- My fan goes on only sometimes, when it overheats it's only on about 30% of the time, meaning sometimes it's on when it overheats, and sometimes it isn't. This points to a faulty thermostat.

Here are the possible causes I'm guessing may be the culprit:

- faulty thermostat
- old coolant (time for flush/refill)
- faulty radiator cap
- faulty water pump
- leaky headgasket
- air bubble in coolant system

Being a cheap bastard like I am, I hope that the issues are contained in the smiley brackets. If it's a water pump - oh well, I've budgeted for it to go bad. If it's the headgasket, well...I can't afford labor, so I'll be bustin' out the Haynes and gettin' to work!

Ideas?

NVturbo

Replace your temperature sending unit....they do go bad more often than most peple think.....cost = around $13.00 and you don't necessarily need to buy OEM either.....

Jared

what you describe sounds like classic symptoms of a bad thermostat, especially this one:

"When the overheating issue occurred and I had a chance to pop my hood (usually I'm in a rush to get to my class so I can't always check it), I check the upper hose, which is immediately hot to the touch, whereas the lower hose is relatively cold. Not freezing, I can feel the warmth, but nowhere near the upper hose."

boostincoupe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jared &raquo;</TD></TR><TR><TD CLASS="quote">what you describe sounds like classic symptoms of a bad thermostat.</TD></TR></TABLE>

Beautiful. I'll be fixing it tomorrow. But do you guys think my water pump is okay, being 114k old?

Night_Minx

compression test will rule out/confirm the headgasket.

10secondhatch

What you need to do is put it on the limiter for about a half hour maybe 45 mins. Go give that a try

HXMan

I had the problem of overheating, and the temp gauge would go up and down also.....I was low on coolant and the radiator had a hole in it.

If you are taking coolant out of the overflow I bet you have a leak somewhere.

If you can pop off the radiator cap.

When I had the problem I was on a kinda long trip, so I just threw water in the radiator so I could make it the rest of the way home.

Once the water was in there the heater worked fine, and the temp no longer fluctuated.

J.R.

Join the club, I have the same symptoms as you in my 92 dx hatch. The only difference is my fan doesnt work. I replaced the thermostat today, and it still over heats. Try the thermostat first.

boostincoupe

Well I solved it...it was my radiator cap.

racinskittle

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Night_Minx &raquo;</TD></TR><TR><TD CLASS="quote">compression test will rule out/confirm the headgasket.

</TD></TR></TABLE>

not always. When the temp gauge is hot, does your heat work at all?

boostincoupe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by racinskittle &raquo;</TD></TR><TR><TD CLASS="quote">

not always. When the temp gauge is hot, does your heat work at all?</TD></TR></TABLE>

My car's not overheating anymore...

boostincoupe

...and it's back from the ******* dead because she's overheating again.

- temp. rises at idle and fluctuates slightly while driving

- overflow fills up (I don't think it's overflowed though, or I'm blind)

- car bogs from time to time, stutters kinda (runs shittier basically)

- however, no white smoke, oil in coolant, coolant in oil

ARP headstuds and OEM headgasket coming soon.