oneEg1Tc

I recently bought a 99 civic and for the first 2 months car never over heated until this weekend. The car starts fine, it does not over heat if i drive it for more than 2 miles. The fan turns on fine the FIRST 3 times but after that for some reason my guge goes over the 3/4, as a last resource I turned on the heater to release some and the gauge went down. I checked the coolant today and everything is filled up, no water on the oil. Before I start trouble shooting it I was wondering if anyone had this problem before, the fan turning on on time at the beginigng but not continously. Any help is appreciated it.

TomCat39

Usually the first step is to bleed the system of air. An air pocket can behave much like you described.

Stealing from one of my other posts on the burping process but from the 5th gen 92-95 civic:

1) Pop rad cap off and bring coolant up to the bottom of the fill neck.
1a) Factory Service Manual says to put the cap on but loose to the first click but I remove it totally for the process.
2) Loosen bleeder bolt where top rad hose goes into head. Once coolant comes out without bubbles, tighten bolt lightly (13 ft-lbs?). (You car does not have this bolt.)
3) Put heater temp to max hot, don't have to turn on heater fan.
4) Start car and the wait begins
5) Raise front of the car if you can
6) Watch bubbles continually come out as you wait for at least twice for the fans to kick on. I like to go 3 times as that's when I finally see the bubbles settle down and become no more.
7) Shut car off, lower the front of the car if you raised it and top up rad to bottom of fill neck
8) Put rad cap on and tighten fully
9) Top up coolant recovery to max line, car will suck any it needs as it cools.
10) The next morning top up the coolant recover to max once again and the car is good to go.

One tip for you, since you are overheating now, I would keep my eye on your temp gauge the whole time you are waiting for the fans to kick on 2-3 times (3 is better).

Also check your oil for a milky coffee like look, if that's present don't bother burping, you have bigger issues.

I would try burping the car first. I would also inspect hoses as I would be wondering why it didn't overheat the first two months and now it has an air pocket?

Anyways, purge the air first to see if that clears it up. If it does and returns in another a few weeks or something or doesn't clear it up, visit back for more diagnostics to run through.

Burping is free so I always start there.

slogfilet

iTrader: (1)

Second vote for burping... if you haven't done it before (using the correct method), do it as soon as possible. If you're doing it right, it should feel like it takes *way* longer than necessary.

TomCat39

This is soooo true. =D

Cheapshot1979

Agreed, air could be in the system. However, once you are satisfied the system has been bled correctly, with the engine warm, pop the cap off the overflow tank while it is running and look for bubbles. If the coolant seems to be boiling inside the overflow, this could be indicative of a more serious problem, such as bad head gasket and/or a warped/cracked cylinder head.

I recently had the problem I described with symptoms much like your car is showing. Coolant was not mixed in with the oil, observed boiling in overflow tank. Head gasket was bad and the head was warped .004". In this case, a head gasket kit and resurfacing the head was the fix.

If the head gasket needs replaced, might as well go ahead and replace the timing belt, a/c belt, p/s belt, and alternator belt while the head is off if you do not know the last time those belts were changed.

oneEg1Tc

So I decided to burp the system again and this time for about 2hrs fan came on as it was supposed to. No major bubbles , I did as well turning the heater on and off , stepping on the gas (not reving) just foot on gas steady . I turned on the ac as well to make sure the ax fan was working and both fans were working. I decide to drive the car for about 40 mins and temperature was ok until I turned the ac on, the temperature rised and my radiator fan did not turned on. I realesed the hot air turning the heater on and got home. I check the Coolant level and my reservoir was all the way to the top. I had left the reservoir just a little under max but once the car over heated this got full all the way to the top.

I burped the system again and took it out for a spin but it over heated again .. At this point I'm lost

Former User

How old is the thermostat? If old, replace it and go from there.

Also, jump the fan switch connector on the thermostat housing. This will make the fan run constantly. Does this prevent the overheating?

oneEg1Tc

the age of the thermostat in unknow, i noticed that once i put the radiator cap on and drove the car for an hour everything seems fine, but the morning after once i drive the car for 5 miles or rev it thats when it starts over heating.If i turn on the heater the temperature goes down and if i turn it off it stays cool for 30 mins. But again the reserviour gets full.

Former User

Good reason to replace.

Also, if you don't have a bone stock 99 Civic, add the mods to your first post.

chrysler kid

Change the thermostat and inspect all heater hoses behind the intake for signs of leaking.

oneEg1Tc

Car is stock .. I guess I'll replace the thermostat and go from there . I was hesitant about it do to the fact that it opens while I burp the system. Could it be bad even tho it opens during that time ?


I checked for leaks and nothing

Jimi Hondrix

Get a combustion leak test done on the coolant..possible head gasket leak. Overheating may have warped head. Mine had the same symptom...coolant loss overfilling into reservoir and radiator always needing to be refilled daily. Maybe you will get lucky and a new radiator cap will fix it.

Former User

Yes.

You would need to run the test below to know if the thermostat is good.

oneEg1Tc

new oem thermostat

oneEg1Tc

Old thermostat

Joseph Michaud

I've never bothered testing a thermostat, though in your case it might be warranted to see if it's the source of your issue.

I figure if I have it apart that far, I just replace it.

TomCat39

I think you may have missed the detail that this thread's last post was 2 years ago. A reply is highly unlikely.

Joseph Michaud

True that. Topic overrun on my phone. Didn't notice I had scrolled into the "similar messages"

tony_2018

They need to do away with that feature, its hard to get to the bottom of a page to reply if they do that on the mobile sites.