hoiguibbo

Hi civic forums' people, I have a 1995 civic EX. I came here to ask about my engine's temperature issues. Lately I have noticed that my car's temp gauge needle rises up from 1/4(normal) to 1/2 (unusual) level. This was first noticed when I was on the way to work (Norwalk) coming from my gf's school (Ucla).So that is about a 40 mile drive. The temp gauge did not rise up up until I was about 4 to 8 miles away to my destination. Considering this was in the morning and weather was cool, I thought it was just glitch somewhere in the engine. But then when I was on the way home from work which was only like 6mile drive, my temp went up again to half way mark. I got concern so I hitched a ride and did not drive the car the next day for work.. I decided to get my car looked at the next day and my trustworthy mechanic to not worry about it because it was only half way. If it went up more than half that's when he is going to check it because it could just be the hot weather causing it (LA weather). However, I had my engine coolant flushed anyways just to make sure that it wasn't that causing the issue either and because I haven't changed it since I bought the car. $55 down the drain. So yeah I came home with a peace of mind hoping it was just the weather... the friday that week I visited my girl again. On the way to her school, I noticed my temp going up a few miles until my destination.. At this point I was getting worried already. Good thing we did not have much planned that and parked my car all day while I was hanging out at their school. So in the evening at around 10 I was driving home, same problem my car's temp would not go up until a long period of driving. In that case, the temp rose up more than half way mark and at 3/4 this time.

Today, I brought my car to my mechanic and explained to him that it wasn't just the weather that was causing it because I drove my car at night when my car started to overheat. They diagnosed my car: drove it once around the block, revved the engine at certain rpms and at one point revved it high rpm when I explained that it would only rise up when I drive @70mph and go back down when I slow down back at 60mph..

Their diagnosis was the radiator going bad. After all the checking and revving the engine. The mechanic seemed to have checked thoroughly to have concluded to that diagnosis (I was there). He used a snake camera to check through the engine block and found no water or coolant contamination, so he said it is not bad head gasket. He also said not my water pump nor hoses. Thermostat was okay. After checking the different parts of the engine's temperature using the digital "lasergun" temperature reader. He had concluded than it was the radiator and read over 200 degrees around some parts of the engine. Fan was working fine too. Thermostat had to be replaced just in case and the radiator. After the work was done on my car, mechanic said it was good to go. Drove it around 5pm (94 degree weather) and got on the freeway, about 5-6 miles of driving the engine was fine at 1/4 the normal reading until I exited it went up half way. My heart rate also went up just as the temp did. I wanted to panic and call my mechanic but the shop was already closing.

Now my question is, should I still be worried after they replaced my radiator and thermostat. Maybe this time it could just be the weather considering it is 90 plus degrees outside. I wanted to create this post urgently while everything is still new and I do not want to wait until the issue gets worst to start asking questions from you guys. What could possibly the problem, is it the head gasket's early sign of going bad and too hard to diagnose because it hasn't done major damage to the engine yet? could it be the water pump, hoses, any leaks, the fan or am I just being paranoid and should consider driving it farther after the repair since half way mark on the temp gauge is considered normal or okay. Thank You!!

ezone

Is the radiator still completely full at the times it seems to get hot?


Could the gauge be lying to you? False reading?

I'd be connecting a scanner to it (would need a scanner and adapter for older Hondas, it's not the common OBD2) and reading coolant temp as seen by the engine computer, comparing to the gauge...and see where everything is at when the gauge goes high.

Then come up with a next step and a plan.

hoiguibbo

yes the radiator is still full when it gets hot.
I would do those methods myself but instead I'd suggest those methods to my mechanic tomorrow because I don't have the tools. I would hope that it could be just the gauge lying to me or any other smaller symptoms like such because they're affordable compared to head gasket. could it be my transmission housing be heating up too much since I do have a bad rear main seal leak? I hope to find out the real answer tomorrow on my visit back to the mechanic. I'm stressed as hell.... I'll keep this up to date. Thank you for your time Ezone

ezone

Many shops won't have the scanner capability either.

Pre-OBD2 is too old for many to be purchasing tools for (too little ROI) unless they have been around 15-20 years or more and got the tools back when they would have been in use regularly.

No, that wouldn't be it.

hoiguibbo

I was hoping bad transmission can cause the car to overheat since the engine could work harder to compensate. The transmission has been leaking due to bad rear main seal (or any other tranny leak) for almost a year now but I did top it off 4 or 5mos. Ago.

If not the bad tranny leak is causing the overheat, what could it be? My mechanic have ruled out everything including head gasket (no white smoke, no water and coolant contamination in the oil). Or they might have over looked my water pump? The belt to it? Or temp sensor? Help..

Daily driver, 1995 civic ex, i don't race. 154k miles.

ezone

A rear main seal is on the engine, not the trans. It would leak engine oil, not trans fluid.

There are many other ways a head gasket can fail.

It's driven by the timing belt.
Impeller related overheating problems should be more prevalent at low RPM, not high (in my mind).

Already suggested (inaccurate gauge issues)

hoiguibbo

So what's causing it to overheat when I drive for a long period (10-15miles) at 60-70mph is by a head gasket? What If it doesn't over heat driving on side street though? Seems to me you are leaning towards that conclusion which is the head gasket. Fml, I hope not. I'm on a tight budget, college student(not using cliche) who happens to be a civic enthusiast which is the reason why I bought this car. But it's given me this problem and only owned it for a year.

Having to spent $350 so far on this issue alone is alot: new radiator, thermostat and coolant. Replaced coolant before they diagnosed more serious problem that they thought was the radiator.

ezone

No, I did not say that.


I was pointing out that if your mechanic is only looking at two possible indications for a head gasket problem, he is lacking looking for about 10 other possible indicators.

There's probably a dozen or more different ways a head gasket can fail, steam from the tailpipe and mixing fluids are only but two possible symptoms.




Does the radiator cap hold pressure when installed on the radiator?

hoiguibbo

The issue had been resolved today. Thanks to my mechanic and to you ezone for the advices. The issue seemed to be the rad fan not turning on sometimes when it needs to. The mechanic did not over look that issue yesterday since I saw the fan working while he was diagnosing it. Therefore he ruled that one out. But there must have been faulty wiring or the fan system just did not work well on the freeway and after a long period of time. Today he tested the fan again and it did not work this time so he just had to bypass it. Temp gauge looking great so far at 1/4 mark as the normal reading.. My question though is that, will a bypass a long term fix or have to save up for a switch and/or sensor. I want the factory setting back but if this work just fine then yeah, suggestions?thank you

ezone

Seems odd that it would run hot at highway speeds without the fan, because there should be plenty of ram-air flowing through the radiator at that speed.....UNLESS there is dense traffic in front of you blocking air flow.
(In NASCAR, drafting can cause the rear vehicles to run hot due to air flow being blocked by the lead car.)

Yes, the fan needs to work, and if he has it wired to run all the time you will burn out the fan motor much sooner than if it was working as designed.

IF he managed to catch it in the act of failing to run, then he SHOULD be able to figure out exactly why it didn't turn on correctly. (Electrical isn't a strong point for 3/4 of mechanics though.)