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Cooling Question 258 - high temps!

6K views 68 replies 22 participants last post by  valkadesh 
#1 ·
I recently put a rebuilt 258 in my 85 CJ7. It was performed by a local shop and a new water pump was installed at the same time. After i got everything back, i went ahead and installed an autometer electrical temperature gauge so i could see exactly what i was running at.

Driving around town, i'm sitting pretty constantly at 210. My sending unit is on the drivers side of the of the engine block right near the firewall. EGR is hooked up

However, when i get going at a good speed ~60 or so, for any period of time, the temperature starts to creep up. After a brief 5 minute drive at that speed, i was already up to 225 and climbing.

I'm assuming the thermostat is working (and new), because when it heats up around 210, i can see it move back a bit telling me the thermostat has opened up and coolant is flowing.

I have what looks like a 6/7 blade fan (not sure if it's a clutch fan or not). Shroud is installed.

I'm really scared to take it on the interstate for any period of time. Prior to putting in the new engine, my last motor overheated on the interstate and boiled coolant everywhere!

I'm thinking it's the radiator perhaps, but i'm not sure. Also i have a warn 8274 up front which sure isn't helping the air flow.

Ideas? bigger radiator?

Thanks!
 
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#31 · (Edited)
Just got done pulling the radiator out to drop it off to get checked tomorrow. The lower hose definitely doesn't have a spring and wasn't even very "firm", i could see it getting sucked in as being a potential problem.

However, where the heck do you find a hose with a reinforcing spring in it? None of the standard parts stores around me had one, just the standard hose. Anyone has a part number or idea?

I went ahead and returned the flex-a-lite setup, as i had a tight return window for a full refund and it wouldn't fit my current radiator. So i thought while i had everything out, i'd go ahead and replace the fan clutch, i can't tell what kind of shape it's in. It's cheap enough it's worth doing i figure.

Thanks for all the help, i'm hoping to have this sorted this week! :cheers2:
 
#32 ·
One thing you might consider is you may be running a 195 thermostat. I *think* that may be stock, and 195 is supposed to be more efficient with fuel injection anyway. The three core is a must as far as I'm concerned. I have the water pump that came on my cj new in 1975 with a 160 degree thermostat, a 7 blade clutchless solid fan, and a three core radiator that runs 180-200 on the interstate.
 
#35 ·
Another update:

I decided to take the old radiator to the shop to get it checked out. I'll have it back tomorrrow and should know how "bad" it was. I also picked up a new lower radiator hose from NAPA (i couldn't find one with a spring in it anywhere),and the new fan clutch should also be in tomorrow.

I'll get all that thrown on by mid-week and give it a spin. If that doesn't fix it i'm moving on to the water pump (which i highly doubt), engine timing and vacuum advance.

I'll move to a 3-core last since i don't even think it'll fit (at least no one can agree), plus the 2 core HD should be more than adequate for a stock 258...

Again, thanks, i'll post back mid-week.
 
#37 ·
I also picked up a new lower radiator hose from NAPA (i couldn't find one with a spring in it anywhere.
Any spring that fits internal to the lower radiator hoze will work fine. It just keeps the hoze from sucking shut/ pinching. The auto store should have one if not ck your jeep dealer. This is a common item and should be avail at multiple locations.

If only two years old did not need a new hose. The internal spring is what you want.

I just called Napa and ORiley for you and both do not carry the spring by itself. Both said the new hose quality does not need an interal spring. I am not sure if sold on this or not. I would try and find a SS spring in the 1.5" or smaller range and just find one that fits internal.

ORiley did carry a rubber flex hose with the spring internal. If that is the same diameter then you could use the spring or the whole product.

A call to the local jeep dealer is also in order. So... I called the jeep dealer and they no longer carry the hose for the 258. Suggested you go to Napa and look at all the hozes and look for one with a spring and try to match the 1.5" ID and then you have a good combo. With spring you eliminate the hose sucking closed and can fix or find out what the issue is.

Regards,
Fred

Here is an article I found on quick search. Good info and I believe both arguments. So for our old CJ's with old radiators there is a need for the spring. The second gentlemans point on internal press is also good. Since the problem is at hwy speed and high rpms and this is high flow/vacuum levels I think the hose is sucking closed. New hose maybe still enough to stop the collasp but once in there for a few yrs and gets softer this problem may come back. On old cars/jeeps I will use/change to a lower press radiator cap from 16 psi to 8/9psi. The lower press equals, lower boing temp, also lowers the internal hose press and can suck closed easier as said in the lower web article.

WEB ARTICLE
Re: lower radiator hose

--------------------------------------------------------------------------------

Quote:
Originally Posted by joe_peters
I would say that the hose collapsing issue was known to the SAE engineers working for Jeep, otherwise the factory hoses would not have come with the springs in them to prevent the collapse.

So, now that the aftermarket (and dealer too?) hoses don't come with the springs, the therory has been put forward that because of improved hose construction the spring is no longer required. My view of mankind is that it is cheaper without the spring, thus no spring.

I advise you find a SS spring of the appropriate size and install it.

The only time I can see the need for the spring is on a cold start up just as the thermostat opens and the flow surges, and the internal coolant pressure (versus ambient) is still low. Until the thermostat opens the only flow is through the heater core or renix bottle (the by pass). Once the coolant warms up just a little the internal pressure quickly exceeds the external pressure, especially in the open system which should have no air in it. Pressure build up is much more gradual in the renix since it has air in the coolant bottle all the time, so the renix system may have had more need for the spring. I could see a lower hose collapsing if the thermostat and or radiator are partially blocked, but in that case the spring is not solving the real problem, which is blockage.

Just out of curiosity, how many people here permanently solved an overheating problem by adding a missing a spring? How many developed an overheating problem by leaving the spring out?

All my fluid mechanics and thermodynamics education tells me if that lower hose collapses on a warmed up system, it is due to a low pressure area in that hose, caused by a pump sucking on a clogged radiator or stuck thermostat.
 
#36 ·
I'll add one thing to this thread. I don't necessarily think it is your issue, but worth checking.

I had an issue with the new gauges (and the old ones I was running) where the temp gauge was reading high. Autometer suggested that I run a dedicated "ground" to ensure I was getting a good ground on this. Turned out that it fixed the issue. I was running a ground off the main center gauge which I guess was causing some signal issues with the ground. I know have a clean ground jump off point inside the cab.

Once I had a good ground in place, temp was showing all normal....

Like I said, may not be your issue, or may only be a part of the issue, but check where your ground is coming from with the gauge, maybe run a temporary right from the battery and see if it changes things.



Ken
 
#38 ·
Fred,

Thanks for checking around, I do really appreciate it! I got the hose at napa, and talked to the manager at length. He gave me the same argument that the newer hoses don't need them. I'm doubting it too, but we'll see.

I'm very curious what the radiator guy will say tomorrow about the state of the radiator. I'm excited to get things thrown back together and give it a spin.

As for the gauge, i already ran a dedicated ground for it, but that's a good idea none-the-less. Thanks.
 
#39 ·
Another update. I got the radiator back today. They took it apart and completely inspected it. They found absolutely nothing. He said it was in great shape. So that rules that out. I got the fan clutch picked up today at lunch to go along with the new hoses.

I guess i'll throw everything back together tonight or tomorrow, but i don't have high hopes.

Thanks to everyone for sticking with me!
 
#40 ·
I think you will be fine when put back together. The clutch fans do wear out and they will not spin enough when hot, so you do not have the right air flow.

Second the new hose is less likely to collasp on the lower hose location. In addition if it goes that way I think it might the lower 20-30 Deg F might keep the hose from getting that soft.

I would also verify you have a 16 psi cap, that will also keep the hose open.

Just a summary and opinion, good luck,
Fred
 
#42 ·
Another update.

I got the 2 core radiator re-installed, the new hoses installed (never could find a spring), new rad cap installed, new fan clutch installed today, and new 50/50 antifreeze put in. Everything bolted up real nice.

To summarize, no real change. I can run about 210 on the interstate which is normal, but without the winch on. It also creeped when i got off the interstate, but just for a second.

I also checked the timing with the engine warm, vacuum advance plugged and disconnected. I was sitting at 4 degrees, which i know is a little on the low side, but i was worried it was too far advanced.

I think i'm done for a while on this. I'm thinking that radiator is just too small, and i'm not positive i can fit a 3 core in. I've only got 1 1/4 clearance with the clutch fan now. I'm guessing the 3 core will knock that down to 1/2 an inch.

I may just end up selling my 8274 and getting something smaller. I just think it's blocking too much air flow and with a 2 core, it can't handle it.

Thanks again to everyone for chiming in!
 
#43 ·
I ran a leaky 3 row 'til I upgraded to a 4 row radiator, no fan shroud on either. The 195* thermostat with no fan clutch and the stock 4 blade fan and never have problems with overheating. The water pump is a stock replacement. Fan belt can't be too tight or loose or it'll slip.
I know some guys don't do it but I drill an 1/8" hole in the thermostat between the outer edge and the center to help get the air out. Then 50/50 water and anti-freeze,
You may need a block flush. I've had water pumps with the vanes rusted off, old thermostat parts and freeze plugs come out during a flush on different engines over the years. Dirt from emergency water fills out of ditches. Rust and debri can really build up in a block. It can settle and displace water to where you are running a lower volume of coolant and restrict water jacket passages even though it doesn't make it's way to the radiator.
A bad freeze plug can leak water when running and suck air when it cools. The plugs in the back of the engine within the bell housing are the ones I thread and install pipe plugs into. The over all cooling system is pretty involved when you start looking over and study it.
We get temps up to 120 around here and most of Ca. get the low 100s during the summer.
 
#44 ·
I've cooled down for a few days now, and i think I've come up with a decent option.

I'm going to go ahead and buy a 3 core radiator, probably the ready-rad RR433583. Now in doing this i'm going to assume (although i'll check), that i won't have enough clearance to fit the 7 blade clutch fan i'm using now.

With that in mind, does anyone sell an adapter to where i can use the same fan, but as a fixed mechanical fan instead of a clutch fan? I basically need a new mount to the waterpump that holds it. I'm not sure if this came stock on any application, but i thought i'd check. In removing the clutch piece, i think i'll have enough clearance. I'd prefer to do this instead of getting a brand new "flex fan", as I've heard horror stories about those.

I figured this way i could keep my existing shroud as well.

Thoughts?
 
#45 ·
Thoughts?
I think you may be thinking too hard about this. Plenty of people run larger radiators and don't have fan interference issues - they even posted so in this thread. If you are worried, ask the vendor which side the additional core has been added on and/or have them give you a measurement from the mounting flange to the core surface. Otherwise, mock-up the 3-core when it arrives. As long as your motor mounts are good, your body bushing under the radiator is good, and your grille support rods are adjusted properly (there is adjustibility in those), you don't need a whole lot of clearance between the thermal clutch and the radiator.
 
#46 ·
I have the 3 core, with shroud and fan clutch also have A/C and it runs about 190 to 195 here in Texas weather. The clearence between fan hub and radiator is 1 inch on the I-6 engine. No spring in lower hose.
Good luck in getting it solved soon.
 
#48 ·
I spoke to a Jeep owning/Rock crawling radiator repair shop guy about this the other day and he told me that the lack of a spring in the hose is not an over-heating issue. He said that the only way a hose can collapse is if there's blockage somewhere else in the system. A collapsed hose is a symptom, not a cause. The only way a hose can cause a restrictive overheating problem is if it's clogged, or, it is so old and weak that it sags or kinks and restricts flow. But that would have to be a really nasty, overly soft hose.

I would look into a flushing of the entire system too. While rebuilding my 85 258, I turned the block over and ran air into the water jacket and big mounds of rust the consistancy of coarse sand blew out the ports. Probably three big handfulls. Surprised the heck out of me. All that crap had to have a negative effect on the overall temp and efficiency.
 
#49 ·
I'm really scared to take it on the interstate for any period of time. Prior to putting in the new engine, my last motor overheated on the interstate and boiled coolant everywhere!
so is this rebuilt motor doing the same, physically boiling coolant out the tube and/or into the bottle ?

are the fan blades on backwards ? pushing instead of pulling ?

hold a towel up against the grille at 2000 rpm; the suction should hold the towel against the grille.

I've seen 2 instances in 30 years where the coolant jacket where the temp sender is installed is plugged; the sender reads the cylinder head temp, ie, no water getting to the sender bulb; remove the sending unit; is water present ?

if the radiator has been checked thoroughly by a competent shop, it's not the problem; engine should stay cool with factory 2 row if everything is working properly.
 
#50 ·
It's not boiling it over, but it probably would, i'm watching my temps really close. The new fan clutch and blades suck air like crazy, that's certainly not the problem. If i loosen the sender, coolant flows out, so it's getting there too. The radiator also checked out squeaky clean, as it should be only 2 years old with limited miles on it since!

I just ordered a 3 core radiator tonight, should be in soon. I'm curious to see how the fit is!
 
#51 · (Edited)
I'm half hesitant to throw this out because of the likely pot-stirring that will occur but retarded timing will increase temps. Higher temp thermos, retarted/ported advance etc. was all part of meeting emissions requirements. I'm not saying that that's the entire problem as I don't believe it is but if your cooling system is maxed out, it sure might be the straw that broke the camels back.

I re-curved my dizzy to what the engine needed to run well, not what the engineers needed to pass emissions, went to properly set up manifold vacuum, base timed it at 8* and lower water temps were a nice little bonus to the added performance.

Are you dead-positive that your fuel and ignition curves are correct? Lean and retarded can really build up the heat. Also, I don't recall if it's been covered here but how is your exhaust? If you're running a fairly-plugged cat or restriction elsewhere, you'll likely have a lot of backpressure under a good load, like on the highway, and that won't let the cylinder clear out very well leaving nice hot exhaust in there. That can certainly escalate your issue as well.

This little heat issue has given you fits and I hope it all turns out well.

http://www.fyurl.com/rr.php?c=2&site=www.jeepforum.com&url=http://performancecarbscience.com
 
#52 ·
My exhaust manifolds are brand new. Cat & muffler are about 2 years old with about 3000 miles on them. My exhaust should be in excellent condition.

I haven't really played much with the curve on the distributor since i got the jeep. During the team rush, i didn't look at or change out any of the springs, and i haven't touched the allen wrench hole, where the vacuum advance plugs into the distributor.

I've probably read 50-75 thread on here on this topic, spoken to a few knowledgeable people locally, and done some other research. With that said, i'm really hoping it's the radiator not being big enough. The spiking of temperature for a few seconds when i get off the interstate seems to be a sign to some that my radiator is too small to properly displace heat.

Hopefully this will be resolved soon. It's insane (and embarrassing) that this has turned into a 50 post thread!
 
#53 ·
didnt your year jeep come stock with the serp belt? was it changed to v belt when they put on the injection possibly? reason i ask is " maybe " your pump is going in the wrong direction?? i know this was discussed prior but i would double check this. especially if a new pump was installed for that particular year jeep.

also, one thing i came across years ago was a backwards installed thermostat - if its upside down in the housing this will cause your issue.

a buddy of mine was dealing with the same issue on a v8 installed jeep and he tried everything to fix this same sort of issue. how he fixed this was drilling a 1/8th inch hole in the thermostat to burp the air.

its got to be something simple that is being overlooked.

one other thing i saw in the past was a small rag in and engine block during a rebuild that someone forgot to remove, i know its a long shot but these are some things i have come across in my years of wrenchin on stuff....

keep us posted.
 
#54 ·
I'm almost positive mine came with the V-belt setup. If it was was supposed to be a serp belt, the fan would be spinning the wrong way. Right now that clutch fan is definitely "sucking" correctly.

I haven't pulled out the thermostat, but i suppose i could.

I've checked the water pump part number that was purchased by my shop and it was the correct one. Now, could they have put the wrong part in the box, it's a possibility.
 
#56 ·
Well here is the latest. I'm stuck at the moment. I got in the 3 core radiatior from ready-rad #443583, and there is no way it'll fit with the clutch fan. I may have 1/4 inch of clearance or it may be touching. I didn't actually install it, but i measured it a few different ways. Either way it's going to be way too tight. So i can't use that with my current clutch fan setup.

I also went to replace the thermostat and cracked the housing reinstalling it. I'm waiting to get a new one it, but it's been a pain to seal even using some permatex.

I'm really beyond sick of messing with this now. I may drop it off at my shop and have them finish it up one way or another.

I'll probably try it with the fresh thermostat and give it a whirl, and if that doesn't fix it maybe try and move to a 4 blade mechanical fan with the 3 core radiator. The water pump is also a possibility still i suppose although i'm pretty sure it's got the right one.

Unfortunately, the weather has really cooled in Nashville, so it's going to be a tough comparison. 95 degree+ to upper 70s-low 80s, is a big difference.

Don't worry, i'll fix it somehow, and be sure to post updates. I hate threads that don't end with the conclusion!
 
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