Cooling System Confusion

[BCRAWLER]

I have a 81 Cherokee 360 v-8 that has had overheating issues recently.The temp just keeps climbing so after 15 minutes of city driving it is over. Temp hit 220 and still climbing. Take it out on the highway and she hits 230 in 2 minutes from 180. No thermostat installed right now cause just wanted to eliminate that as a problem. First issue has be solved.The lower rad hose would collapse at anything just over idle. I now can get about 20-25 minutes of city driving before it overheats. Just finished running Gunk rad cleaner thru it and not much has changed. I do see flow thru the rad with the cap off.Pulled the water pump off and found that there is about 2/3 of the impeller blades still left.There is no play in the pump shaft so unsure why the impellers are shorter than the new unit at the parts store.Have seen on here on other posts that the cooling systems are marginal at best.Is this my issue. My other concern is the rad not flowing enough.Had something interesting happen. With the rad cap office,engine at 180,reved the motor up to 3 grand and watched the lower new molded hose collapse until I backed it off.There should be no air in the system as i do see flow.It is running propane and have the timing at 22 with the vacuum advance disconnected.Any advice is greatly appreciated.

[REDONE]

The stupid tiny buttons on my stupid smart phone resulted in a premature partial post. Sorry.

[REDONE]

The factory cooling was more than adequate when in new or like new condition. I would speculate that your radiator is in significantly less than like new condition. Granted the pump missing 1/3 of its impeller is less than optimal, the fact that the lower radiator hose collapses tells me the flow restriction is in the radiator.

[BCRAWLER]

Is there any way to check the flow on the rad.Putting a garden hose on the top and watching the flow coming out I do not believe is the best option.The water seems to come out as fast as it goes in and as soon as i shut of the supply the flow coming out stops. A new rad here is near $400.And I thought I was the only one with big finger syndrome.

[REDONE]

Have you tried squeezing the upper rad hose when the lower hose is collapsing? If its firm then the obstruction is definitely in the radiator. Unfortunately, flow isn't the only thing that can make a radiator junk. Gunk can make it junk too. As scale builds up in the tubes it insulates them so they don't transfer heat as efficiently. You can look into having your radiator rodded and rebuilt, sometimes it's cheaper than a new radiator, sometimes not.

[jaber]

Find you a lower rad hose spring and put into it. It will keep the lower hose from collapsing, eliminating the restriction.

[BCRAWLER]

Changed the fluid a bunch of times today to try and rinse out the Gunk brand rad flush. Seems to run around 180 now on highway and city with a outside temperature of 70.Seems rad was plugged and the rad flush cleared out enough to run for now until I can afford to replace the 2 core with a 4 core unit.Thanx for the help.

[csuengr]

Put the thermostat back in. It provides a restriction (head) that keeps the pump from cavitating. Cavitation will result in a loss of flow.

[BCRAWLER]

Will do once I have confirmed all is good,thanx for the reminder though.

[serehill]

Wow first you have a flimsy radiator hose this is a phenomenon that is only happening with the cap off & no pressure right?? You don't have to have the steel spring but that's up to you if this line collapses with cap on & 12 pounds of pressure that would be a problem. I would like to see that. The impeller can loose more than half of it's ability to circulate with 30 % of the impeller gone. If the hose doesn't collapse when pressurized & it shouldn't then it is not the problem. You still could have a restricted radiator.
The impeller is an important player in the system but it goes conflict the ability to suck the hose flat. If the impeller was that bad you couldn't suck the hose flat. Put the cap on & if you can't suck the hose flat then it's not part of your problem. I've seen the collapse when the cap is removed of the use of a cheap hose not the greatest but not the problem when pressurized if you can collapse it then that would be very interesting. A close t stat with no pressure can do that too. An impeller can not pull but a couple of pounds of pressure the heat will create from 12 to 15 + pounds of pressure. The radiator can create a restriction on a flimsy hose & not be stopped up but that doesn't mean it isn't stopped up though. The eroded impeller as stated with & does cause cavitation at high rpms & can be the sole cause since you say you see circulation. Have you used a flashlight to look at the tubes inside the radiator. What do they look like?

[BCRAWLER]

With the first lower rad it would collapse with or without the cap on.Assumed the hose was a new unit.When I went to replace it saw that under the lower hose clamp it did not look like a new relatively shiny unit. Looking at the inside of it I thought it maybe as old as my kids. For fun shot it with some AmourAll original and wow ,uniform appearance.Put the new hose on and it did it with the cap off and never checked with the cap on.Live in a small town with only 2 parts stores. Called the local place and asked for a lower rad hose for a Jeep with the wire and was told that it was not available.Could get me a hose in a couple of days.Called the 2nd place and only asked for a lower molded hose which they had in stock. Should have said something about the wire unit. Turns out the sell generic bendable hoses with the wire in them. Just need length and size of end. Opps.Found that out when I went back to have another look at the new pump.Figured if the pump could collapse the hose it probably was working some what.Took a look at the pump and the first thing I saw was manufactured in China.Alarm bells started going off.The pump was some what different.Included in the box were 2 spacer tubes of different lengths.Turns out that the large bolts above and below the pump input require these spacers due to a difference in the casting.Checked the impellers and there was a difference.The space between the front edge of the impeller blade and the housing were the same,the difference being that on the new unit the blades were longer. The pump had a longer shaft to make up the difference and the base of the impeller sat closer to the timing cover.Wonder if it would have rubbed against the cover.When it collapsed with the new hose I realized the problem had to be the rad.Could not suck enough water thru so something had to take its place.Looked into the rad thru the top and the tubes looked fine at that end.Thinking that the scale might start from the bottom and work its way up I decided to run the most aggressive rad flush they had anyways.Said to run for 15 minutes then remove.I ran it for 1/2 a hour then flushed it a couple of times.Some flush was still in there but it was getting dark out and beer was calling.Went out early next morning and flushed several times before testing.Flow seemed improved and lower hose never collapsed.Took it for a test drive and all seemed good. Just got to check TSM as the cap on it is a 7 pound unit.Being propane fueled causes it to run hotter and a older style upright winch blocking air flow slightly i am happy to see a 180* temperature reading.Just going to run it for a few days before reinstalling the 165* thermostat.Thanx to one and all who provided advice .

[carnuck]

I have a used V8 rad here in Seattle for $50. I think it's 3 core. Redline water wetter will also help your temps drop.

[haminawag]

Before you trash that two row radiator, you need to know that it is designed to cool a system 35% larger than the one you have. If you're gonna hot rod the GW then maybe a 4 row would be ok. Two rows are great and HIGHLY under-rated.

If you pull the radiator and fill it to the top with the hose nipples plugged, it should drain completely within 20 seconds when you unplug the lower hose nipple, longer than that and it should be flushed thoroughly, and the entire system should be REVERSE flushed to remove scale and lime deposits. Always keep a good hose spring in the lower hose. Always run the correct thermostat. Always use a 50/50 mixture of NEW antifreeze. And flush and replace that antifreeze YEARLY. AND REMEMBER...ANY rust in a cooling system is ABNORMAL. Good luck.