Slicer1989

99 LX, 223k miles. Today while going on the interstate, the temp went way up (not near the H mark, but still way higher than normal) so I turned my heat on, and it went back down for a little bit.... Pulled off freeway, sitting in traffic it did the same thing again.

On the way home, did the same thing, went way up, then went back down again - I got home and noticed the bottom radiator hose didn't feel all that warm or like it had any fluid in it... the top hose was piping hot, but not the bottom hose.

Added coolant, tried burping it again, and the hose got a little more warm, but still nothing compared to the top

Any ideas?

ezone

You had to add coolant, where?
If the radiator was low, WHY was it low?

They can overheat even with less than a quart missing from the radiator.


Those blow head gaskets just like the 7th gens do, with all the same mysterious symptoms.

Slicer1989

into the radiator, the overflow was low as well.

I've no idea where it's going, Oil looks fine, No coolant in it, Exhaust smells and looks good, seems to be no coolant lost there - And I don't see any visible leaks on the outside.

Guess I'll look into replacing the headgasket soon. Are there any sure-fire ways to tell if it's bad?

sdaidoji

iTrader: (1)

if it is similar to the 7th gen, try the tests in the videos on the first post.

https://www.civicforums.com/forums/3...reference.html

Wankenstein

Don't rush to a blown head gasket conclusion so quickly. There's other ways an engine can overheat besides a thermostat being stuck closed or a headgasket breach.

Radiator fan not engaging
Waterpump failing or completely failed
Debris in front of radiator impeding air flow
Clogged radiator
External leak that causes low coolant level

Slicer1989

New Radiator + flushed coolant
Fan working like it should
Nothing in front of radiator
And I can't see or detect in external leaks. All hoses are fine.

The one thing that leads me to believe it's a thermostat being wonky, is the bottom radiator hose was warm, but not hot.... and the top one, well I couldn't put my hands on it.... I was told that was a way to tell if it was bad

ezone

If the radiator is doing its job, this could be normal and correct. The radiator is SUPPOSED to cool the hot liquid that goes in at the top.

If the thermostat was stuck closed, there would be little or no liquid flow through the radiator...which would also result in what you state above.
More investigation may be needed to discern between the two.


If you refill the radiator and burp the cooling system of trapped air, does it no longer run hot or overheat while you drive? (at least not until the radiator goes low again)

Slicer1989

Replaced the thermostat today, The old one looked pretty crusty, and alot of the rubber on it was in bad shape. The temp didn't spike at all today, Even with a few hard pulls. no leaks, nothing bubbling over, etc.... But only time will tell.

Slicer1989

Well I guess the next thing to replace is my Water pump, Or get it tested for bad HG. I ran almost 3 weeks with no issues, even sitting and idling it was fine - Today I was at Autozone trying to get some wipers and left the car running, Came out and the temp was way over "normal" but not close to the H mark.. as soon as I revved the engine, it started going back down - as soon as I drove, it returned to normal mark. Didn't see or smell any coolant leaks, Didn't hear any bubbling or anything.... I also didn't know if my fan was on or not....

Wankenstein

Make sure radiator fan is engaging properly...turn on the air conditioner and the radiator fan should come on. After that turn off a/c and let engine idle and clock how long it takes for radiator fan to engage again. If rad-fan is engaging properly then might be situation below.

One way (possibly only way) to check the waterpump is to remove the rad-cap at cold start and allow engine to reach operating temp. At operating temp look (from as far away as possible) inside the radiator opening while at idle and then rev engine to observe coolant flow/current...flow should increase with rpms. Being that you stated the temp gauge returned to normal temp when you revved the engine does point to a weak/failing water-pump.

If you're going to replace the water-pump and it's within 10k miles of/or unknown last timing belt replacement it would be a good time to replace the timing belt, tensioner, waterpump, crank seal and accessory belts.

ezone

So is the radiator now low? It took almost 3 weeks to push or lose enough liquid out of the radiator to cause a problem.....


Refill radiator and it's all good for another 2.5 weeks?
I seriously doubt a water pump problem unless that's where it's leaking....unless it's been running on straight water for a long time

Would be nice to know for sure if the radiator fans were running at the time, or not.

Wankenstein

His statement "as soon as I revved the engine, it (temp gauge) started going back down" got me thinking that at idle possibly the waterpump isn't spinning as it it should (failing but not completely failed) and when he revved it, it engages the waterpump enough to work properly or at least enough to lower the engine temp. Then he stated "as soon as I drove, it returned to normal mark" increased air flow through radiator assisted pump to get it to normal operating temp.

In reply#6 he stated "fan is working like it should". In reply#9 "I also didn't know if my fan was on or not"
It's a bit confusing?

Slicer1989

I don't know if there is any fluid loss or not - It had been running far too long for me to check... Checked oil this morning, No mixture, Drove for a while, checked oil, look the same... Exhaust doesn't have any smells or smoke, even when stepping on it.

2 of those week was spent driving 50+ miles a day for 4-5 days a week for work, and no issues.

I figured if the water pump was going bad, it wouldn't be so intermittent. But I've only ever had them fail by the bearings going out in a obviously noticeable way.

The Thermostat was Honda OEM... Radiator is from O'rielys... Heat was and is working fine, didn't get cold or cool on me even at idle. Drove it again earlier with no issues... Even did some hard pulls.

I can't say I've heard the fans run that much, The few times I do hear them run, It's for a short period of time.. Very short.

My A/C doesn't work (Belt is gone, and looks like it has been for a while)(

I planned on doing the timing belt soon anyways, since I don't know the service history of it.... gonna do everything else as well. What's the BEST kit out there for this?

And if it is HG, since I have NOT overheated the engine... Will it be as simple as just swapping gasket, or would I NEED to get the head resurfaced?

ezone

Have the head measured for flatness by a machinist. If it's within spec, slap the new head gasket on and go.

If it measures as warped (0.002" is max warp spec) then it must be straightened/resurfaced.

sdaidoji

iTrader: (1)

For such an involved and labor intensive job, I choose to use all OE. It lasted 94k on mine, so good enough for price.

Ah, I hear non OE rad cap have some quirks too.

Wankenstein

When engine is cold check radiator and reservoir for coolant levels.
Have you performed a pressure test on the coolant system to completely rule out external leaks?

My dad ran straight six Chevy 250's in his boat and the waterpumps on those would act sporatically/intermittenly for a few weeks until he would replace them before they completely fail. I've never had a waterpump issue with the Honda's I've owned and there doesn't seem to be many threads concerning them other than during timing belt replacement.

If it will idle without temp gauge raising..let it idle about 20 minutes and the fan should briefly engage around two times.

A leak-down test (Ezone style/ EZ1) with straight (no leakdown tester attached) 125-150 psi compressed air while each cylinder is at TDC will confirm whether or not the head gasket is breached. When doing this test if there is a breach there will be bubbles in the coolant system:

D17VTECPOWER

iTrader: (1)

Have the cooling system pressure tested. The coolant obviously went somewhere. Also, the top hose should be hotter than the bottom one. If you consistently get good heat, I wouldn't suspect the head gasket being bad though.

Slicer1989

So I checked the levels, they were completely fine... The overflow / reservoir was a LITTLE low... but I've NEVER had a car that at some point wasn't a little low, it wasn't bone dry, but low... Even my ex gf's 2010 Prius got low at times.

Hasn't done it again since... Even did some EXTREMELY hard pulls on the freeway today, and the temp didn't budge.

Idled in traffic, temp was fine... heat never went cold...

So I am confused. Maybe fault temp sensor?

D17VTECPOWER

iTrader: (1)

It could be a bad temp sensor. I think that a cooling fan or thermostat problem is much more likely though. Also, the coolant level shouldn't significantly drop over time. It's supposed to be a sealed system. If the level is dropping, the coolant is going somewhere. I would suggest pressure testing the system. Since the car is doing fine now, I'm not worried about the head gasket. If it overheats again, pull over and open the hood and see if the radiator fan is on. Also, feel the upper and lower radiator hoses for temperature.

ezone

A head gasket breach can be extremely small and slow in the early stages.
Some people don't discover they have a problem until they take an extended highway trip of several hundred miles....and weather plays a big part in which "low coolant level" symptoms might be noticed.


Everything may go back to normal after the radiator is refilled and burped (assuming no serious damage from minor overheating).......until it's been driven long enough for the head gasket breach to displace liquid out of the radiator again.


1000+ miles between noticeable events is entirely possible in the beginning...

But if your reservoir level continues dropping, look for leakage externally....maybe look for dried green (or blue) crusty trails at the water pump weep hole and hose fittings.