Fan shroud / motor heating on highway

I have changed hose this morning. Was in stock on my local car parts , gates 26612. Really hard to put in place , seems 2’’ too long and 1 side have may be 1/8 less than 1 3/4 ! But now it’s ok. Impossible to collapse . Old one was easy whit thumbs and 1 finger at ambiant temperature , may be smooter when coolant is at 195 deg !! I hope it was the problem ! I remove water pump fan , only keep the electric one . I don’t see the difference when put back the fixed fan last summer. Problem was the same .

If you could squeeze the lower hose with a thumb and one finger when it was ambient, that would definitely be one of, or the whole problem. Good find!

If you hang around on this site long enough, you will inevitably come across a jewell of information like this one! I've been trying to figure out why my van would run hotter going highway speeds than it would in stop and go traffic. So I changed my lower radiator hose to one with a spring inside it and guess what? Problem solved! Thanks Michel and everyone else that contributes their insight.

CONGRATS!!! That is awesome!!!
Now drive it like ya stole it.

Hope my problem Will be ok too ! I cant run now, we received 10’’ of snow wednesday and 7’’ more friday. We have about 5 feets snow in front of my door garage . It will go in april ! But hope problem will be resolved ! Happy to read that it work for you !

I finally run Many Time at outside temp about 28-30 degre since i have changed the bottom rad hose whit one rigid and i still have same problem ! All is ok except when run 30-40 min at 2300-2500 rpm ( 55-70 mph ) , motor temp rise up 185-190-195 deg , and thermostat is 180 deg. ( new one , same problem since change ) . Timing is total 36 at 2500 rpm, hi have a direct drive fan , and Électric fan ( for idle) ! 307 have that heat problem or its an other problem on mine ? Bad Timing , bad rad , bad water pump, no fan shroud ( no on mine ) . When less than 25 outside , its not go over 185 !!! So what it can be ?

190 - 195 doesn't sound too bad. That's what mine runs at.

Yes but thermostat is 180. Not supposed to go over ? Its like the water pump dont have thé good flow or if thé radiator is not enough.

Any idea ?

Original pump and rad are supposed to run motor at Max 180 when outside temp is under 27-28 deg ?

Possible to have better rad ?

Total timing can change thé heat at 2300-2500 rpm ?

Maybe I missed it.?You may have done a flush already. But when doing a flush make sure to flush the heater core by itself as well. Disconnect both heater hoses on the engine side and flush one side with a high pressure hose while watching the brown gunk come out the other heater hose until it's clear. Switch sides and do the same until it runs clear. If the heater hoses are old I would replace those with new. Those are narrow passageways and deposits harden up in there and restrict flow. I skipped the heater core when having a similar overheating issue. I flushed the engine block only, replaced water pump, new gaskets, new radiator hoses, recored radiator. Temperatures still went up. I decided to include flushing the heater core and get new heater hoses. Temperatures have been at about 180.

I just read your thread once again from the beginning. Says new thermostat and changed fan on water pump. I learned that changing one thing here and then another thing there didn't really fix things right away. Now I go through the full system. That includes taking off and inspecting all items like water necks, thermostat housings, thermostat, water pump, radiator and hoses. While those are off, might as well install new replacement water pump, hoses, and gaskets. Radiator should be professionally flushed or hot tanked. I had mine recored while I was at it...and  still engine block has to be flushed with good pressure of water. Do the same with heater core as I mentioned earlier. When I took my water pump off, one of the fins inside the water pump rotating wheel was eaten up by rust, probably contributing to less flow. A new water pump was cheap. Get your radiator inspected. If you can get more cores installed the better if not just have it flushed clean. When you put everything together at least you know everything is flushed properly and everything is replaced with new. But definitely flush the heater core! Timing can make your engine run hot. Have it professionally timed after you have your cooling completely gone through.

Heater core is new from last year. It was leaking inside van on passenger floor, so i changed it and its ok. Problèm was there before and after heater core changed ( specially made for my van ) .

Radiator was changes by previous owner ( bill jr radiator service , recore radiator r# spec 385$ 01-18-2012 ) and new water pump ( 53$ ) installed same date when make complete overall by mitchells garage ! Van have about 2000 miles since ( i have invoice from guys ). So if i trust invoice , rad and pump and all hose are new . Engin was overhaul ! Maybe need to be flushed, and put water press on all to clean ( rad , Heather, hoses and motor ) ? .

Well, if all has been done to it, the last thing is getting air out of the cooling system, or what is called burping the radiator. Air gets trapped in the system whenever someone changes something in the system like thermostat and they just put the cap back on. Parking on an incline or putting the van on jack stands while you do that will help air escape. Turn van on with radiator cap off, at 180 the thermostat should open up and begin letting air out through the tubes. You need to keep adding fluid only as needed to keep the fluid up. You'll see air bubbles forming indicating air coming out. I'm about to install that 2nd gen radiator and top tank system on mine. I heard it was designed with the metal tube as a "T" in the middle of the top radiator hose to connect back to the top tank and eliminate air in the system. I know man. A problem like this can be a headache. Hopefully it's just trapped air. If it's clean fluid you can save it if you flush.

I have thé original rad i think, whit thé small round tank on the top. Like you can see in the First page !

I need to rise up thé front ?  About 2 feets ?

Maybe just a foot, or while parked on a hill to get the air out of the radiator. . Going over 180 is only happening on highway speeds? You still haven't gotten the correct fan shroud? I'm confused if you're running the mechanical one attached to pump or an electric one or both. If you have the original one attached to the pump you definitely do need the correct shroud so air passes through the radiator correctly. So you would have been correct in thinking that since the beginning. It seems with the V8s the fan clutch is necessary as well. If you are running an electric fan and shroud it's a different story. You have to make sure it's a puller fan and not a pusher fan on the engine side. Try burping it. Hopefully if it's just air trapped you can let it out. But do get a correct fan shroud and clutch. Post a wanted ad. Or have a shroud  made. And post a picture of your engine/radiator/fan setup if you can.

I have a fan bolted on the pump and also an electric fan that start at idle( or slow speed ) when more than 180. Both fan are between rad and motor and take air from rad to the motor! Electric one only work a slow speed ( under 30-40mph ) , not on highway ( probe is on the rad ) . I have no shroud, nothing. And problem is only when go at more than 2000 rpm ( more than 50 mph ) steady more than 20-25 minute when its more than 25 deg outside ! So problem is the shroud ? Where i can find it ?

You shouldn't have both fans between radiator and motor. Have you tried just the electric fan and removing the water pump fan? Your fan is triggered at 180 but your thermostat is 180 also, and that can be a problem if you want to run your electric fan. 180 is a good thermostat for using water pump fan. When does it go off? A good setting to shut off can be at 165. This is a good description I've read at hotrod while looking at Mark VIII electric fan info "In a healthy cooling system, the cooling fan controls how hot an engine gets, and the thermostat regulates how cold the motor gets. Hence, it’s important to select a thermostat that opens up below the cooling fan activation threshold. If the thermostat opens at a temperature above the activation threshold of the fan, then the fan will run continuously regardless of how well the radiator dissipates heat". In that article Hot rod used a
160 thermostat, the fan would go on at 180 and shut off at 165 (set up by thermostat switch). if you want to give your electric fan another chance you can change out your thermostat to a 160 and see how your temperature behaves then.



But To get it working like stock I would take off electric fan from motor side. It is restricting air flow for the mechanical fan. Install a clutch on to the fan or without clutch and add a shroud. The clutch just free spins when engine doesn't need to be cooled so engine can warm up faster and clutch locks to spin with engine speed when needing cooling.   Some members here on this site vintage-vans.com or on VCVC.org  might have a fan shroud. You have to post an ad on parts wanted on each site to see if someone has a spare they can sell you. It's a hard part to get, but someone might have one to sell. Some people do put electric fans as a puller fan on engine side with good results but eliminate the mechanical fan. A good electric fan I've heard good things about is the Mark VIII fan because it has high EFM and a good shroud. You can probably google Mark VIII fan to get more info. You might find that hot rod article. For now maybe finish getting air out of your system while adding more fluid, and Maybe test out yor system using 160 thermostat and electric fan. Post a wanted ad for the shroud in the meantime.

I aready run whitout pump fan and same trouble .  Thé electric fan dont start  on highway when gauge is 195 because probe is in the rad and have wind ! ( i think ). When slow down , under 40-45 mph , electric fan go on ( less wind ) . When put  on electric fan + pump fan,  same trouble except take more Time to go at  195 au gauge!   Maybe electric fan cause restriction !

In hot weather, up to 200 degrees could be expected from a 180 thermostat, but your outside temp is 28-30 degrees?...….Do you have the proper mix of fresh coolant?....Do you have ice or snow clogging the radiator fins?...…. The fastest and easiest experiment I can suggest is to gut a thermostat and install just the disc (basically no thermostat) and run it and see what it does......I have run my daily driver for over two years without a stat, but I live in a very hot place.....In cold climates the stat is necessary....

Yesterday Evening it was only 15 degré outside, and run about 30-40 min and i never see temps go more than 185, so it mean that stat and water pump work fine ?  Its the rad that not work fine in hot temp ( bad  rad or missing shroud ) ?

Collant is about -30 !  

How test if water pump do his job ?

I still have problem when its more than 25 deg outside!  

Problem is missing fan shroud or a bad radiator ?

my 68 had many overheating problems, when I 1st got it (2007)heads were off, little did I know that it had a cracked head(Pass side) found out hard way) & cracked ex manifold Luckily Mark sent a Lot of extra parts including a recorded HD rad. even with new WP  new fan clutch  6 blade fan & shroud it still run hot .
Part of the reason for putting LS motor in(Made Heck of a Deal)
I think my problem was block was Gunked up with rust & probably stop leak??
Hope this Helps some . you did a Ton of work & a lot of $$ Hope you find the problem so you can cruise with No worries. In this Crazy time.
(been driving mine to help get Away from it  for awhile)

I dont think i have craked head because oil and coolan are always ok, color and level.


But today i found that :  the front  insulating is not glued on the frame ( or front of engin bay ) .  So when run on Highway, it may go on the radiator and block half of that one.  Possible or not ? Picture taked under the van between 2 slot of the wind defector

A thermostat sets the MINIMUM temperature at which the coolant will circulate between the radiator and engine.....better air flow might gain an extra 5 or 10 degrees drop, but the thermostat will resist any extra efficiency beyond that.....If you want to know the true efficiency of your cooling system, install a gutted thermostat...

If you believe that insulation is laying against the front of the radiator, it's gotta go!... The inside of the box should be coated with elastomeric paint and insulation should be on the interior side of the sheet metal...

Hi. I still have the same problem. When run 20-25 min on high way at 60-70 mph , temps go to 195-200 ! Whit or whit out fixed fan , and whit or whit out inside electric fan. I need a good shroud fan or a puller fan the other side of the rad ?