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changing radiator in 88 Accord


dderolph
07-23-2009, 05:13 PM
This car recently lost coolant quickly and the temperature rose way above normal while my son was driving it. He added some coolant at a service station and was able to drive back home.

By the time he got back, the coolant level was quite low again. The next day, I filled the radiator and started the car to try to observe where the leak was occurring. Before starting the car, no leakage occurred. After the car ran long enough for the coolant to start getting hot, it started leaking. So, it seems like this leak is pressure-sensitive. In other words, when it the coolant gets warm/hot and pressure in the cooling system increases, it leaks.

I could not see the exact spot where the leak occurs but it definitely seems to be coming from the radiator area, not from hoses or hose connections on the engine or the water pump. One aspect of this I noticed is that the top hose got hot during this warmup and commencement of leaking but the bottom hose did not feel hot yet. So, I'm wondering whether the radiator is clogged, which would contribute to pressure buildup.

I had hoped to remove the panel under the radiator so that I could observe exactly where the leak is located, from underneath the car (wearing eye protection and using precaution not to burned). I raised the car and took out a few bolts. I encountered a problem with removing the panel. A bolt on the right side of the car can not be taken out because the nut, which I presume is supposed welded to the car or otherwise be locked in place so that it will not turn when the bolt is being unscrewed, turns when I turn the bolt. So, I can't remove the panel.

I was thinking I would need to remove that panel to change radiators. But, now I'm wondering whether it can be removed from above by pulling the two fans out first. Can someone confirm whether the radiator can be removed from above without removing the panel underneath? Of course, I would need to removed the bottom hose from the radiator also.

mpumas
07-23-2009, 08:48 PM
Changing the radiator is not hard but you need to get the panel off to remove the bottom hose and if an automatic to remove the transmission hoses. You might have a stuck thermostat which would cause the water to boil out. Honda does things differently then most, the bottom hose is the outlet of the engine, the top hose is the cooler water to the engine. So if the bottom hose does not get hot, water is not circulating. You can remove the radiator cap and the bottom hose then fill through the radiator cap to see if the radiator is clogged.

dderolph
07-23-2009, 08:59 PM
I forgot to mention, it's a manual transmission.

Thanks for the tips. Unfortunately, as I said, I can't see any way of getting the lower panel off due to a bolt not coming off. It looks to my like the panel would have to basically be ripped or cut off, which would most likely destroy it. I think I may need to take it to a shop; perhaps they will know how to remove that panel, and get it reinstalled once the radiator is replaced (assuming that's the problem).

If the fans are completely removed, could the bottom hose be disconnected from above, rather than from underneath?

jeffcoslacker
07-24-2009, 05:08 AM
Usually. Sometimes they are diabolical and have the clamp for the hose turned where you can only get access from underneath. But if you are replacing the radiator anyway you can usually lift it up once it's free and gain access that way, or disconnect it from the motor end.

Honda radiators typically fail where the upper or lower tank joins the core, or the tank itself will crack. Many times they won't leak much at all until the thermostat opens and flow begins in the radiator (which is right at the moment you describe where the top hose is just beginning to warm)...there's a good chance it's not full to the top either, and if the top tank is the culprit, the area around the crack will not even be submerged until coolant circulation begins. These are vertical flow radiators, water is pushing through from top to bottom, so as the thermostat opens, water rushes into the top tank, and leakage begins, see?

I've seen many (including my own) that had a 2" crack in the top tank that you couldn't see anything happening until the moment the thermostat first opened, and then it just poured out under pressure...old horizontal flow radiators if you had a leak at the top, it would only leak down that far and stop, you could still limp around with a leak...vertical flow units, since it's pushing water into the top tank from the motor under pump pressure once the thermostat opens, will empty the entire cooling system out a topside leak very quickly...

That's what I suspect is happening. Eventually, the lower hose should warm if it were let run. Typically the upper hose will not get hot if the thermostat is not opening...not until the motor begins to overheat anyway...if you can hold the upper hose after a cold start, and feel the rush of heat moving from the motor end to the radiator end that comes on pretty suddenly after 4-5 minutes of operation, the thermostat is probably working.

Sometimes you can lock a Vice Grip on those stubborn lower cover bolts and pull outward while turning, and get them to stop spinning the nut or stripping threads...

dderolph
07-24-2009, 09:04 AM
jeffcoslacker, thanks for your reply. Your description seems right on target.

But if you are replacing the radiator anyway you can usually lift it up once it's free and gain access that way, or disconnect it from the motor end.Ah, so I could disconnect the hose from the motor end, remove the radiator with the hose attached, and then remove the hose. Great!

Now, what about removing those fans? Will that be more difficult without taking the bottom panel off? I've located bolts at the top of the fans and those will be easy to remove. But, are there bolts at the bottom of the fans, also?

jeffcoslacker
07-24-2009, 07:57 PM
I think so, there was on my '95, been a long time since I did a rad on one as old as yours.

Tell you what....take a look at your car's parts list on

http://www.hondaautomotiveparts.com/auto/jsp/mws/PartsSearch.jsp

You can look up the diagram of every part of the car and get an idea what it looks like in detail before diving into a repair...helps a lot...

You'll probably need to look under "radiator" in the part field to see the fan(s)

dderolph
08-19-2009, 11:06 AM
Thought I'd let you know I got this done; did not get it done until a few weeks after the last post here.

I was able to remove the old radiator and install the new one without removing that panel below the radiator. But, I was not able to do it exactly as advised, i.e. by leaving the bottom water hose connected to the radiator and disconnecting the hose at the other end. I tried that but had difficulty trying to get the hose disconnected from the engine block. So, with the hose still connected at both ends, I lifted the radiator part way out, rotating it somewhat to keep the bottom hose connector still low but giving me clear enough access to the clamp on that connection to losen it and then disconnect the hose from the radiator.

As I recall, I spent around 2 1/2 hours to assess how to remove the old radiator and to actually do it. With two fans to remove and an A/C hose interferring with removal of fans, it was a tortuous ordeal. I still have not replaced the bolts that fasten the bottom of the fans to the radiator. The old bolts were very rusty. I may buy new ones to use there.

In retrospect, I think removing the radiator with fans attached, then removing fans and connecting them to the new radiator before installing it might have been an option.

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