Cooling passage blockage or radiator blockage?

[Gwamp]

I have some form of blockage in the cooling system in my 75 waggie. Is there some way to tell where the blockage is? How does one tell if your radiator is not flowing water the way it should? Are there any additives that can help to clean out the passages in your motor?

My days hav been filled with the following fun:

1)fill up the cooling system.

2)start Jeep

3)motor warms up and the thermostat seems to open as I can see coolant flow past the fill tube.

4)10-15 seconds later, the motor overheats and coolant explodes out the fill tube and jeep get shut off.

5)rinse and repeat.

ideas?

[illegalFSJ]

What do you mean by the "fill tube"?
To see if the thermostat is actually opening, put your hand on the upper radiator hose as the engine heats up. If the motor overheats and the upper hose is cold or lukewarm, replace the thermostat.
Also try this with the lower radiator hose. If there's a blockage in the radiator, the lower hose will not warm up. If the system is functioning normally, the lower hose will be warm, but not hot to the touch. If you're overheating with a hot upper hose, and a stone cold lower hose, I'd take the radiator out to a radiator shop and have it boiled out.

Also feel the heater hoses for warmth. They should warm up pretty quick.

[Gwamp]

Originally posted by illegalFSJ:
What do you mean by the "fill tube"?
.the place where you add water. the neck or whatever. I cannot for the life of me remember the right term right now! :D

[illegalFSJ]

LOL, you mean that hole under the radiator cap?!?!?

[Don S]

..
Gwamp:

... Make a plug that you can screw a garden hose into that you can clamp on the lower radiator hose. Turn on the garden hose. Now roll the truck on its top and shake it... Maybe some of that green dog goo I remember seeing will pour out of the top of the radiator.

... Some of the freeze plugs are easy to R&R. Remove the thermostat and put the hose plug in the upper hose, turn the truck right side up again and try to flush the green stuff out of the block. Make sure the heater circuit is flowing.
Quit eating at Taco Bell !!
Good luck and http://www.michiganjeepers.com/forums/images/graemlins/wave.gif and … CUL.. Don S..

[Gwamp]

Originally posted by illegalFSJ:
LOL, you mean that hole under the radiator cap?!?!?That one right there! :D

[Gwamp]

Originally posted by Don S:
..
Gwamp: Quit eating at Taco Bell !!Dang it! What if I don't want to quit eating there? :D

[Don S]

Originally posted by Gwamp:
</font><blockquote>quote:</font><hr />Originally posted by Don S:
..
Gwamp: Quit eating at Taco Bell !!Dang it! What if I don't want to quit eating there? :D </font>[/QUOTE]..
Gwamp:

... I thought that's where your truck got infested with all that green goo that was in the 'rear area' a year ago ??? I used to have a gif that show why but I lost it. :mad: I think I still have a URL to one of those old threads... But I'll bet it's been disposed of ... least I hope so.. :rolleyes:
http://www.boylover.net/ubb/graemlins/bat_angel.gif
Have a good one http://www.michiganjeepers.com/forums/images/graemlins/popcorn.gif and CUL.. Don S..

ps... A lot of old topics have disappeared

[oldyellowwagoneer]

Head gasket?

[Gwamp]

Originally posted by scoutgrl:
Head gasket?If it was that, I would have fouled antifreeze or coolant in the oil wouldn't I? Both are clean. The motor in this rig is one that I pulled out of another rig and just "freshened" it with a new cam, timing chain and gears, re-built the oil pump and slapped an edelbrock setup on top of it and put it into this waggie. Everything sounds good in the motor and it runs great except for this glaring issue.

[kyjman]

What is the pressure rating on the rad cap? If its not the right one it could be building too much pressure and causing this.
Just a thought.

[oldyellowwagoneer]

It could be leaking between a coolant passage and cylinder or a cracked head, neither will necessarily leak into the oil pan. Use a pressure tester on the radiator to find out for sure.
QUOTE
If it was that, I would have fouled antifreeze or coolant in the oil wouldn't I? Both are clean.
END QUOTE

Dennis

[Gwamp]

Well crap! I don't really want ot pull the heads on this POS. Hopefully it will turn out to be clogged radiator or something simple

[oldyellowwagoneer]

Originally posted by Gwamp:
Well crap! I don't really want ot pull the heads on this POS. Hopefully it will turn out to be clogged radiator or something simpleThats still a possibility, Just confirm with a pressure tester to make sure. A head gaskets still cheaper than a new radiator.I have a great radiator shop I go to and they never try to cheat me as we run quite a few radiators through there from the truck stop I work for. The problem with our old jeeps is the cores are all pretty old and rarely can be reused . Out of the last 5 jeep radiators I've sent in only 1 was useable and a re-core is just as expensive as a new one with a much better warranty(lifetime). Dennis

[ January 12, 2004, 09:44 PM: Message edited by: scoutgrl ]

[J10/J20 Project]

Is there a spring in the bottom radiator hose? If not there should be one.

[ January 12, 2004, 09:44 PM: Message edited by: J10/J20 Project ]

[gsmikie]

compression test

[Buggzz]

Originally posted by Gwamp:
I have some form of blockage in the cooling system in my 75 waggie. Is there some way to tell where the blockage is? How does one tell if your radiator is not flowing water the way it should? Are there any additives that can help to clean out the passages in your motor?I know I will probably get beaten up for saying this, but I have flushed my radiator, and run a mixture of "spic-n-span" and water for a week. After a week, flush the radiator again until no soap comes out, and then fill with Antifreeze. Of course only do this in the summer when freezing temps are not possible.

The gunk that comes out of the radiator during the second flush is amazing, and the radiator core looks brand new (I assume the engine passages look that way too.)

My dad and I have done this to several cars over the years, and have never had any ill effects.

For the record:
'80 pinto - 186K miles before wrecked (My first Car, no jokes please.)
'84 LTD - 224K miles before sold
'90 Crown Vic - 250K miles
'93 Cougar - 186K miles and counting.

[Gwamp]

Originally posted by J10/J20 Project:
Is there a spring in the bottom radiator hose? If not there should be one.There is a spring in the bottom hose. I am leaning towards clogged radiator on this. Mostly becasue I had some overheating issues with the prior motor as well.

I should run a compression test as well just to see if anything is out of the ordinary. We shall see. I picked up a new radiator cap and some radiator "colon blow" from the local NAPA. we shall see!

[illegalFSJ]

Tell us the results of the hose test!
Does the upper hose get hot?
Does the lower hose get warm?
Do the heater hoses get hot?
Does the coolant bypass hose get hot?
Tell us now!

[Gwamp]

Originally posted by illegalFSJ:
Tell us the results of the hose test!
Does the upper hose get hot?
Does the lower hose get warm?
Do the heater hoses get hot?
Does the coolant bypass hose get hot?
Tell us now!I haven't had a chance to get to all that good stuff yet! I just got the new cap yesterday! paitence grasshopper! :D If the weather stays decent today, I hope to figure out this particular mystery! Hopefully I will get to this today as tomorrow is right out as I am picking up 2 new rather large objects to clutter up the yard and street. ;)

[ January 13, 2004, 07:04 AM: Message edited by: Gwamp ]

[Gwamp]

I love it when the problem turns out to be hte simplest of the things it could be. Clogged radiator it is! All hoses in system hot, top of radiator hot. Bottom hose cold. I am glad that I have 2 spares in the besement!

[Lister]

What is the spring in the bottom hose for?

[Don S]

..

Lister;
The spring prevents the hose from collapsing when the water pump is putting negative pressure in it i.e. sucking. :D

Have a good one, http://www.michiganjeepers.com/forums/images/graemlins/wave.gif and … CUL.. Don S..

[Wesdog]

Gwamp,

You might want to consider a coolant filter. Scale etc. from that refreshed engine may have clogged your radiator:

http://www.jag-lovers.org/xj-s/book/CoolantFilters.html

I use a gano filter in-line with my upper radiator hose. http://www.catsradiator.com/gano.htm

[Gwamp]

That is entirely possible that the radiator gave up the ghost as you say with the scale from the motor. I was having some overheating issues with this rig before with a different motor in it. I think that I am going to gove the motor a good colon blow before I install one of my other radiators in it. :D

[letank]

Wondering the good and bad of such a filter....

http://www.mako.com.au/

and for US customers

http://www.tefba.com/

I have not financial benefits in posting this....

and the simplest idea is to install a brass garden hose fittings with the screen on the heater circuit to prevent a sudden blockage on the main circuit, as specs above

http://www.jag-lovers.org/xj-s/book/CoolantFilters.html

[serehill]

I love it when the problem turns out to be hte simplest of the things it could be. Clogged radiator it is! All hoses in system hot, top of radiator hot. Bottom hose cold. I am glad that I have 2 spares in the besement!

Earlier you stated that you could see the thermostat open. Claiming circulation was your proof. If you see good circulation then the bottom hose can not be cold. It would have to have water circulating through it to see circulation right?. Also a stoppage in circulaion would be happening & you would see slight to no flow not good flow. The thermostat closing (being stuck) would do this & because of the bypass hose you would still see little circulation. Don't eliminate the t stat.
Have you checked the radiator cap to ensure there are no cracks in the rubber.

Years ago I did this with a mustang & I had a little circulation & assumed it was a radiator stopped up. I bought a new one put it on & had the same problem. I ulled the tstat & changed it & it fixed the problem.
It does sound like the radiator is a good common denominator for 2 different engines.
But:
I know it's a fishing expedition but if you're seeing good circulation you can't have a stopped system or tstat. If you have what looks like restricted flow it could be the tstat.
Last but not least a water pump could have an issue if there is flow restriction.

Just thoughts & opinions I know there's not a solution just suggestions. Something isn't making sense on the process of elimination.