patoloco008

Hi all,

I just bought this car (Accord 98 EX automatic) and of course after two days of driving it it overheated. I stated looking for water leaks and found several. First I replaced the water outlet which houses the thermostat. When I opened it I actually saw that there was NO thermostat so I put in a new one. I also saw that what appears to be the temp sensor was disconnected so I connected it. I replaced the metal pipe which runs from the thermostat to the water pump and noticed the monoblock was corroded so had to put some sealant around the o-ring to stop the leak. Next, I saw that water was bleeding through the weep hole of the water pump so had a mechanic change the water pump and the timing belt. Now there are no more leaks but the car is still overheating.

I make sure to take all the air out when topping the rad with water (not putting in coolant until I fix this). I bought a new radiator cap. I've inspected all the hoses - they look fine. Still water keeps overflowing and overfilling the overflow tank by the radiator - I hear bubbling noises. The temp gauge does not show any overheating and the car runs and idles fine but when I open the hood I can see that it is overheating. There are no signs of blown head gasket (don't see white smoke on start, don't see any oil film in the rad water, oil looks fine - not milky). Both fans turn on and off although it takes them awhile.

Any ideas? I am thinking that the thermostat from Autozone is not the correct one (I would love to get an OEM part but I am in Mexico and it takes weeks to get these things delivered from the agency). Could the temp sensor be bad - how do I check it?

On a probably unrelated note I also noticed that the alternator signal fuse is missing so I put a new one in but that made the car not shut off ( I could take the key out and it would still keep running) so I had to take the fuse back out. I am planning to look into this after I fix the overheating problem but thought I would mention it in case the two are connected somehow.

Sorry this is so long but I've spent a looong time trying to fix it so wanted to give some 'history' Would really appreciate some input! Thanks!

djkurious

Thanks for the history. Looks as if someone really rigged that car. No thermostat? What were they thinking? I wouldn't trust those autozone thermostats...

You need to pressure test the system. You can loan the tool from a parts store.

leflore

Agree with djcurious. Seems like you have ruled out everything. Wonder if the radiator is clogged up

holmesnmanny

i would compression test it just to completely rule out head gasket leak

patoloco008

Thanks guys. I'll try to find a place to do the compression test.

Btw I just took out the temp sensor this morning and tested the resistance (by sticking it in some luke warm water and then in some boiling water) and it measured ok (~1300 Ohms down to ~330 Ohms). It is also receiving exactly 5V so I think I have ruled that out as well.

mrj_accord

sounds like a clogged radiator. u might want to have them pressure test it. looking thru the fill cap does it look dirty inside, clogged fins, color of antifreeze?

Jjbaehr

Time for a head gasket, looks like exhaust gas is getting into the cooling system, get a block checker, if it turns yellow you got a problem

patoloco008

Thanks for all the replies. I tried to find someone to pressure test the cooling system but everyone looks at me as I am crazy - this is Mexico (Playa del Carmen) and no one that I asked has heard of such a thing. At Autozone I made them look in their catalog and they said they can special order the tester for me for $400. Ouch.

But anyway, I looked at the oil cap where you pour in the oil this morning and I did see milky residue at the very top at the cap (before I was checking the oil just at looking at the dip stick). So as Jjbaer says, it sounds like it is time for a new head gasket. I am going to try to change it myself, what do you think? I am mechanically inclined although I don't have much experience but I am learning a lot with this car, lol. I am going to search this site/online for a good diy tutorial/video. If you know of some good ones I would appreciate some links. Any other tips, other things to change, look for, etc while I take the head off?

Thanks for all the help.

patoloco008

Just to add three more things that I noticed though: the car has trouble starting once it gets to operating temp (no problem starting when cold), the temp needle inside the dash never actually gets up to the middle (stays at about one third) and there is no heat coming from the vents (the blower motor works but don't notice any difference when I turn the dial from cold to warm - although the ac doesn't work and it is very hot here I still would think that there should be some difference). Also I have the system filled up with water only (no coolant).

I also took out the radiator a few days ago and ran some water through it - it was flowing pretty well and I didn't notice any leaks although I am sure under pressure might be a different story...

Anyway, I am going to order the head gasket from Honda and keep looking a cooling system pressure tester and a block tester just to make sure...

Jjbaehr

It's a fairly straight foward job, you are gonna wanna change the timing and balance shaft belts when you do it, along with a water pump. Make sure you check the head for warp age once it's off. If its above .008 the head is junk. If its more than.002 it Needs to be resurfaced and pressure checked. Adjust the valves once its back together. Then thoroughly bleed the cooling system.

Jjbaehr

As far as the no heat thing I would check and see if the heater core isn't plugged up. I've seen products that claim to "seal leaking head gaskets" be poured into cooling systems and plug up the heater core to the point coolant won't flow thru it. Once the car is warmed up touch each hose going in and coming out with the heat on full blast. It the temp is drastically different between the 2 hoses, you know it's plugged up

lfdelar2

yeah dude try to see if there is no clog in your radiator. Most people take out the thermostat when the head is on its way out. So if your radiator is good then am sorry guey but you might need to get your head replacement or fixed.

361 accord

this is interesting, good luck.

patoloco008

So I checked the hoses that go to the heater core and one was getting hot and the other one was cold. Does that mean that the heater core is plugged up? Could that also cause an overheat? I've read it's a pain to take out the heater core - can I just cancel it? I live in the tropics - no need for heat.

Anyway, the head gasket arrived but I don't want to blow up a second one so I really want to make sure the rest of the system is fine before i bother putting it in.

patoloco008

I disconnected the heater valve and was able to flush the heater core so it is not clogged but the heater valve is stuck closed. That is fine with me as long as it will not cause me overheat problems.

holmesnmanny

here's the deal...a clogged a heater core will not cause your car to overheat.

You need to do a compression test to be sure that your head gasket is leaking and that the coolant system is getting hot because of the head gasket leak.

Do this first, then report back. If the head gasket isn't leaking then obviously you have another reason that the car is overheating and this means you can cancel that head gasket replacement.

patoloco008

I got brave and took out the head. There is corrosion in the engine block almost around all cylinders on the exhaust side!!! A local engine rebuilding shop said they can weld it for me and resurface the block and the head. So I am going to try to take out the block so I can take it to them! They said it should be fairly easy to take out the block at this point. Does anybody have instructions on how to do this or should I just look around and take out everything that's in the way

361 accord

lol if it looks like it is really in the way then in it is.

i might be able to help you out with some diagrams if you needem

holmesnmanny

The very first thing to do when buying a car is to check under the radiator cap. If there's just plain tap water it's best to avoid that car. There will be engine block damage as well as various other damage as a result of running tap water.

patoloco008

Hehe, I might need them for putting everything back together lol. I labeled everything as best as I could and separated my bolts/parts into plastic bags but still I bet I'll be scratching my head a lot when I start to arm it back up.

It was actually full of coolant when I bought it but as we can see this actually doesn't tell you much. Note to self: don't buy a 15 year old car again, lol.

But hey, I didn't know much about cars before and now I pretty much took the whole thing apart and if I manage to put it back together that would have been worth it by itself