Boiling Radiator

[Tentsontop]

What's up all? Every now and then I can hear my radiator boiling (gurgling sound) when I shut it down on really hot days after being in stop/go traffic. I parked once on a side street with a very high crown and it spit a bit of fluid out from the overflow. I'm not sure what's up, but thought I'd start with a flush and then change the thermostat and radiator cap. I don't have any significant leaks that I know of (knock on wood). Nada in the oil, plugs are fine, no funky exhaust smell. We're at 150K on the original HG, so I'm looking into doing that soon.

I'm still cruising the archives, but I'd appreciate any advice on what else to check as well as direction on how to flush the entire system including the heater core.

Thanks!

 

[Romer]

I'd say the flush and refill would do the trick. Changing the thermostat is cheap and easy if you don't know when its been done last and is a good idea. make sure you use the same kind of anit-freeze as is in there now. If you can't tell, do a real good flush before you refill. Make sure you turn the heaters on (front and rear).

 

[MLX450]

Fan Clutch?

 

[Tentsontop]

I think the fan clutch is fine. It's always spinning when I check it out.
Romer - How can I be sure the rear heater is working? I've hit the dash switch a few times over the winter, but I never felt like it was working as I didn't hear a fan or anything. Where are the connectors to flush the heaters and do I flush them with the engine running?

 

[FJBen]

<<<<Hi-Jack>>>>>

Jenny, you should come checkout the CO/WY horsetooth 4wheelers club! We are meeting tuesday 20th at I-25/35 It's our little cruiser club! We need more 80's in the club!!!!

 

[semlin]

check the fluid in the rad first thing in the morning to see if it is low. possibilities include bad rad cap, bad fan clutch, bad t-stat or pinhole leak.

 

[nat88toy]

my buddy's 1988 toy truck did the same thing for a while and was also over heating so we flushed the system, drained the radiator and took it out of the truck to inspect it. Opon inspection we found that 70% of the fins were clogged with mud a good power washing took care of that. We then changed the thermostat. After the new thermostat was in we put the radiator back in and filled it with coolant then drove it 60 miles at 70 mph on a 90* day no more over heating or strange gurgling sounds emitting from the radiator.

(be sure to use a low setting of a power washer so you dont bend over the fins)

 

[CJF]

I think the fan clutch is fine. It's always spinning when I check it out.

That is *not* a valid test. It always spins; the question is whether it's locking up when it should, rather than just free-wheeling.

Curtis

 

[NeverFinis]

Blowing coolant out of the overflow bottle could be a sign of HG failure. Combustion gases are being pushed into the cooling system.

 

[Romer]

On the rear heater. There are hoses that run through the firewall to your rear heater. Do you hear anything when You turn on the switch? You might check the firewall to make sure someone did not bypass these heater lines and thats why your rear heater isn't doing anything. The reason i said run the rear heater is to flush the fluid in those lines as well.

 

[Tentsontop]

I've got my fingers crossed that it isn't the HG. It only spit fluid once. I've only noticed the boiling sound 3 or 4 times in the past month (800 miles). Any recommendations regarding what green coolant to use? It's got green in it now. I've heard the low phosphate stuff is best - whatever that is.

 

[Jason Andrews]

I think the fan clutch is fine. It's always spinning when I check it out.
quote]

Hey Jenny, this doesn't mean the fan clutch is good.

When your truck is really hot turn it off and spin the fan, in the correct direction, to check for resistance. It should be locked up. If it spins freely or more than half a turn you should replace that before anything!

 

[landtank]

When your truck is really hot turn it off and spin the fan, in the correct direction, to check for resistance.

Did this exact thing today as a matter of fact. Ordered a new fan clutch from AdvancedAuto. My 1 year old blue clutch is s***.

 

[semlin]

landtank, meaning it is failing that test or meanign that it does not seem to be working? I am dubious enough of mine that i'm putting the old one back on to see how it works.

 

[Tentsontop]

<<<<Hi-Jack>>>>>

Jenny, you should come checkout the CO/WY horsetooth 4wheelers club! We are meeting tuesday 20th at I-25/35 It's our little cruiser club! We need more 80's in the club!!!!

I can't make this meeting, but I went on the 7 mile run back in Feb. Mine and Madam's 96 were the only 80s there. I found out that 50lbs of air pressure is no good on ice/snow. I'll try to make a meeting one of these days.

 

[Rich]

On the rear heater. There are hoses that run through the firewall to your rear heater. Do you hear anything when You turn on the switch? You might check the firewall to make sure someone did not bypass these heater lines and thats why your rear heater isn't doing anything. The reason i said run the rear heater is to flush the fluid in those lines as well.

There is only one heater control valve and it controls the coolant flow to both front and rear heaters. The only thing the rear heater switch on the dash does is turn on the rear heater fan located under the drivers seat.

 

[landtank]

landtank, meaning it is failing that test or meanign that it does not seem to be working? I am dubious enough of mine that i'm putting the old one back on to see how it works.

It fails the test and doesn't seem to be working. I pulled over with the truck at around 220* and there was no ROAR from the fan. When I turned the truck off the fan spun freely with little to no resistance. I've done this check before on a good fan and it should not spin freely when warm let alone over temp.

My Blue coupling is no more than 1 years old if my memory serves me correctly.

 

[Romer]

There is only one heater control valve and it controls the coolant flow to both front and rear heaters. The only thing the rear heater switch on the dash does is turn on the rear heater fan located under the drivers seat.

Thanks for clarifying Rich. I know they were separte hoses to the front and rear.

 

[Rookie2]

My Blue coupling is no more than 1 years old if my memory serves me correctly.

Say WHAT!! I thought the new blue OEM one was supposed to be the end of all our fan clutch woes??

Have you talked to C-Dan any about it?

 

[landtank]

Say WHAT!! I thought the new blue OEM one was supposed to be the end of all our fan clutch woes??

Have you talked to C-Dan any about it?

I will once I confirm the diagnosys.