mdmitch2

I want to get some expert opinions before I blow any money on expensive parts., so here's the situation...

I have a 94 dx with around 200k. A few months ago, my water pump went out, and started leaking lots of coolant. We replaced the water pump and thermostat, and everything ran fine until a few days ago when it started to overheat. It is pretty random when it does it, but it is usually when driving in stop and go traffic or idling, and of course running the AC seems to bring it about more often. Sometimes though I can drive around town for an hour with AC on and it won't overheat at all.

Like I said, the water pump and tstat are new, and also the upper and lower hoses are getting plenty hot. The car is not blowing any white smoke at all, and there does not appear to be any indication of a blown HG as far as I can tell. It runs and idles perfectly and my gas mileage is great.

I have already burped the system numerous times and it's definitely not leaking any fluid. I also drained/replaced all the fluid when I replaced the water pump. I just replaced the radiator cap, and I also felt all over the radiator and it seems to be equally hot on all four corners.

I was thinking that maybe the fan wasn't coming on, so I intentionally caused it to overheat and checked the fan when the needle started to get over halfway up the gauge, and the fan was running. However, I then turned the car off and waited a few minutes and turned it back on. This time, it began to overheat again and the fan still hadn't come on by the time it got to 2/3 of the gauge. So last night I replaced the fan switch and ran the car in the driveway for 20 or so minutes with my wife watching the fan. The fan came on after only a few minutes and stayed on for a while. I couldn't get it to overheat or even come close, so I thought I had fixed the problem. Anyway, on my way to work this morning I decided to run the AC full blast just to make sure it was fixed, and sure enough it began overheating as soon as I got to a stop light.

I drove it around town later in the day for probably two more hours with the AC running, and I couldn't get it to overheat again, but I'm sure it will soon.

Sooooo, after all that, what the heck do you genius honda guys think is going on? Bad radiator? Bad coolant temperature sensor? Weak fan motor???? I'm running out of ideas here...

Thanks for reading this long post, and thanks in advance for your responses!

E.Honda

Tstat could be sticking at times.

ls19integra95

thermostat could be sticking or your radiator could be taking a ****, it also could just have crap inside the radiator that will now and then block it up...

WihaSi

I have a 98 EJ6, this exact thing is happening to me...word for word of your description lol.

mdmitch2

well I plan on working on it more tomorrow. I do have a crappy non OEM thermostat even though its more or less brand new. Guess I'll go get a honda one tomorrow, and see if that does it.

MREG2

iTrader: (1)

Sounds just like my 93 DX hatch at 215k miles when the original motor was in it. A few months after I had gotten the car, it did the same exact thing only I wasn't worried about it too much because it didn't do it all the time, only in traffic and at idle. I thought it was the thermostat so I replaced it and kept driving it. I was on my way home from a short trip and the temp gauge pegged out and blew the headgasket on the number one cylinder. I got the car home and did the full headgasket replacement procedure and the since then, the engine never skipped a beat; actually now the motor is in a 92 CX still running strong. Anyways, I would recommend replacing the radiator first, which should cost about $100 plus tax from Advance or O'Reillys and it should be a two row which is much better anyways. If that doesn't fix it then you have a headgasket leaking and eventually it will blow and leave you beside the road like mine did.

Good luck,
Jeremy

ls19integra95

i agree with mreg2, i would replace the radiator and thermostat first because since its been over heating the thermostat might be bad now and most likely its the radiator considering everything else is replaced, if that dont work then its the headgasket

WihaSi

Well crap, this doesn't sound good for my car

95ProjectEJ1

iTrader: (5)

Have you checked the inside of the overflow tank for "gunk"? You can always drain the rad. and flush the system. I know Prestone makes a rad. flush they sell at Autozone and Kragen. Might not cure the problem, but at least you will have some peace of mind knowing you checked another angle.

mdmitch2

me neither! So I guess I'll replace the thermostat and the radiator. Guess it wouldn't hurt to do a compression test on the engine and pressure test the cooling system too...

instructor74

Before you replace the radiator take it to the car was and pressure wash it from inside the bay to the out side you might be shocked what comes out of the cooling fins. Had this happen on my car once. You can also pull the rad out and back flush it to get any crap out of it. Good luck

95ProjectEJ1

iTrader: (5)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by instructor74 &raquo;</TD></TR><TR><TD CLASS="quote">Before you replace the radiator take it to the car was and pressure wash it from inside the bay to the out side you might be shocked what comes out of the cooling fins. Had this happen on my car once. You can also pull the rad out and back flush it to get any crap out of it. Good luck</TD></TR></TABLE>

And if you find that you still want to get a new radiator after this may i suggest looking up RC Autoworks... they have a rad/fan(12") combo for i think around 160 shipped.

mdmitch2

...weird. don't know why it reposted that 6 hours later. anyway, I bought a new OEM tstat, and I'm going to replace that and also flush the radiator tonight (as long as it doesnt rain). thanks for all the responses! I'll keep updating the thread till I fix the problem.

Sketch_hs

Due a leakdown, could be headgasket

headrec*

Check radiator fins for lots of bending or debris blocking flow. Check the compression too. If that doesn't work and compression is good then flush the system out and replace with oem thermostat.

mdmitch2

OK... still overheating with new Honda OEM tstat.

Also, upon closer inspection, the fins do look pretty bad on the radiator. It's OEM honda and I'm fairly certain its never been replaced, so I'm going to pick up a new one tomorrow and hopefully install tomorrow night.

I probably should try to clean it out and pressure wash it/backflush it, etc... but at this point I'm very worried about it getting hot one too many times and blowing the HG like happened to MREG2, so I'm just going to replace it to be safe.

iceman7329

2 days ago mine ran hot, pulled the cap and it was really low on coolant. Filled it up and tonight it started again. Was boiling like before and is low again. I think the HG is blown. Its running like dog **** now.

Preferio

I'm assuming you haven't pressure tested the system, correct?

mdmitch2

I tried renting a pressure tester at three different places, but no one had the correct adapters for a honda radiator. I tried squeezing the upper and lower hoses to see if I could force any fluid out, but I didn't notice any leaks...

Anyway, I'm going out to the car right now to replace the radiator and hoses...

E.Honda

check the fins....make sure you can run water through the outside of the radiator.

My corvette got clogged like that once.

If water is not going through it.....neither is much air.

WDMP

i had the same thing happen to a cx hatch.

replaced the thermo, radiator twice, water pump and it was still randomly overheating. whenever i opened the hood, there would be coolant all over the place. i would always just top it off.

i got sick of it so i was going to replace the hg. my brother decided to do a complete coolant flush as a last resort before the hg, and it ran beautifully since. engine is always cold now and takes forever to warm up.

these engines are weird sometimes and it looks like you've already tried all the easy solutions. dont give up man... thats where all the fun is in these cars.

mdmitch2

so everything seems to be okay with the new radiator. I drove it around a lot today with AC running and couldn't get it to overheat. hopefully its fixed finally! I'm going to do a compression test just out of curiosity...

EGJason

Try a failsafe thermostat. Sounds like you need a few bottles of coolant flush, and flush it a few times.