Slicer1989

I have a 99 Civic LX, Non-VTEC, Autom 222k miles

The temp seems to move around, Usually when it's 90+ outside, I can hear the fan running, coolant level is fine, Just replace rad cap since the old one fell apart as soon as I took it out.

No oil in water, or water in oil... Can't see any visible leaks of coolant on the outside of the engine.

it never goes a little above half? and then sometimes it will go back down to normal range, today it shot way up (Still not close to H) and then went right back down no problem.

Is this sign of head gasket failure?

Slicer1989

Well, After doing some research it seems that I probably have a blown head gasket. The coolant isn't oily, neither is the oil filled with coolant.

But I ran a test I found on the forum, saying if you top the coolant off, and run the engine hard with the cap off and cold, and it burps out alot, that that means it has exhaust gasses getting into the coolant jackets.

Here is a video

https://www.youtube.com/watch?v=L8lZ...ature=youtu.be

310civicEX

nooo it would do that regardless. id do a compression test, see if the gasket failed. and if ur not blowing huge clouds of smoke out of the tailpipe you should be good.

sounds like a thermostat or water pump issue maybe?

Slicer1989

No smoke or water at all out the exhaust, and it doesn't have the sweet smell of burning coolant... it smells like perfectly fine exhaust.

I'm just freaking out, because if it is a head gasket issue, I don't know how to replace it nor could I afford to have a shop do it...

310civicEX

if it was me id look at possible air in coolant system or thermostat.

Slicer1989

I'm limited on tools, and no where to work on my car... I had my hood open for a few hours one day, and the apartment complex I lived in got on my *** about it.

ezone

Video: Not proof yet IMO. Revving up the engine makes the water pump spin faster and that can make coolant spit out the open hole.

If you had used a funnel-fill radiator funnel you could watch in it for the endless stream of bubbles that would indicate air entering the system......(see video in link below)

You could try one of those colored liquid block check tools, but those don't always work when the combustion leak is very slow


Make sure the radiator is completely full and system is burped of all trapped air. If it lost coolant you need to find out why.

With the radiator completely full, radiator cap OFF, and engine cold.... unplug the distributor harness (or remove the ECM fuse, or disconnect the PGMFI main relay) so it cannot run---- and have someone crank the engine while you watch the radiator for coolant to rise and spill out. THAT would be pretty conclusive of a breach



Read this....and see the videos in the first post of this thread:
https://www.civicforums.com/forums/3...reference.html





If the temp gauge needle is just moving around, you could get a scanner or app that displays live ECM data and watch the ECT (coolant temp) value....see if it stays in a normal area when the gauge goes nuts. That might tell you if you just have a gauge or sending unit problem. (gauge and ECM use separate temp sensors)

Slicer1989

It's not even getting close to over heating, it's barely went a little over "middle" when it moves around, and only seems to do it on 90+ degree days.

It's not losing any coolant, I've checked it every day, and after long trips, and neither the radiator or overflow tank has changed (The overflow changes VERY VERY little, like so little it's not a cause for concern IMO)

There is no other symptons of a HG leak or issue... Exhaust is fine, no external leaks (Other than a leaky valve cover gasket) I am gonna clean the engine just to be sure.

310civicEX

im just gonna throw this out there..

when the fan comes on and the thermostat opens..the temp will drop.

ezone

Right...and temp gauge would probably be highest just before that fan kicks on