FJ40 coolant flush (1 Viewer)
- Thread starter cws57
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
I need to burp it. Do I need to give it more time? Twice today I’ve given it 15 minutes.
This thread has the answers I needed, particularly 1 hour not 10 minutes.
forum.ih8mud.com
“After a coolant change, burp the cooling system using the regular tricks of a burping funnel, squeezing the radiator inlet hose, elevating the front of the car and most importantly driving the car for at least an hour. Ignore the temperature gauge. It's not valid and the engine isn't running hot.”
““Normally if the sender isn't burped, after enough driving and hot and cold cycles (which can sometimes take weeks or longer) the gauge needle will eventually settle down to where it normally runs. My guess to what happens is that the air bubble in the sender fitting eventually gets reabsorbed (somehow) or burped out through expansion via heating. At any rate, 2Fs will e v e n t u a l l y clear the air pocket under the sender on their own, but for those of us who don't want to wait around forever for that to happen, you now know what to do.”
Burping the Temperature Sender on a 2F after a Coolant Change
I thought I'd share a discovery I made that was revealed by some testing. I've had suspicions about this for a long time. When the coolant is drained and replaced on a 2F, an air pocket gets created inside the sender's adapter fitting which prevents the sender from being fully immersed in the...
forum.ih8mud.com
“After a coolant change, burp the cooling system using the regular tricks of a burping funnel, squeezing the radiator inlet hose, elevating the front of the car and most importantly driving the car for at least an hour. Ignore the temperature gauge. It's not valid and the engine isn't running hot.”
““Normally if the sender isn't burped, after enough driving and hot and cold cycles (which can sometimes take weeks or longer) the gauge needle will eventually settle down to where it normally runs. My guess to what happens is that the air bubble in the sender fitting eventually gets reabsorbed (somehow) or burped out through expansion via heating. At any rate, 2Fs will e v e n t u a l l y clear the air pocket under the sender on their own, but for those of us who don't want to wait around forever for that to happen, you now know what to do.”
I put something pretty similar to this on the heater hose from the head to the heater core:
www.summitracing.com
First empty, drain under the radiator and under the block, to remove all the old antifreeze.
To flush, hook a garden hose to it and run with the radiator cap off. It's going to constantly add water, so it shouldn't get hot enough to open the thermostat, but run enough water through it to eventually end up with only clean water in the system. You're really only putting in enough water to remove old antifreeze or any other water soluble contaminates. At this stage it's pretty much just water that's running through it and shouldn't need to worry about catching and disposal.
Then open the drains again and empty the water, you don't want the minerals in tap water constantly near boiling in the system.
Refill 50/50 antifreeze and distilled water, or the premixed stuff. Leave the cap off that "T"'s garden hose connector until water comes out or the radiator is totally full, maybe fill some from there once the radiator is full. The air pocket that would typically need "burping" is going to come out this while filling.
And if your in Idaho or Connecticut doing this in January, don't leave it with water only....
And remember that antifreeze lubricates the water pump, don't be running it alot with that.
Dorman 47152 Dorman Radiator Flush Tee Fittings | Summit Racing
Free Shipping - Dorman Radiator Flush Tee Fittings with qualifying orders of $109. Shop Coolant Flush Fittings at Summit Racing.
First empty, drain under the radiator and under the block, to remove all the old antifreeze.
To flush, hook a garden hose to it and run with the radiator cap off. It's going to constantly add water, so it shouldn't get hot enough to open the thermostat, but run enough water through it to eventually end up with only clean water in the system. You're really only putting in enough water to remove old antifreeze or any other water soluble contaminates. At this stage it's pretty much just water that's running through it and shouldn't need to worry about catching and disposal.
Then open the drains again and empty the water, you don't want the minerals in tap water constantly near boiling in the system.
Refill 50/50 antifreeze and distilled water, or the premixed stuff. Leave the cap off that "T"'s garden hose connector until water comes out or the radiator is totally full, maybe fill some from there once the radiator is full. The air pocket that would typically need "burping" is going to come out this while filling.
And if your in Idaho or Connecticut doing this in January, don't leave it with water only....
And remember that antifreeze lubricates the water pump, don't be running it alot with that.
At the risk of getting some eye rolling I persist. I followed those steps. I drained, flushed, ran it 10 miles, flushed again with garden hose in radiator adding while engine block drain removed. Turned off engine and let it all out. Closed the drain and filled with 3 gallons of 50/50. That’s all it would take. Today I drove it 10 miles. The gauge only got up to 1/6. I popped the hood and released the radiator cap. There was some pressure, but not much. Couple of squirts. It didn’t leak all over and spray and burn me. The level was still at the top of the radiator. I could touch it with my finger. Hot, not scalding. Do you still think it’s a burping problem? I think if I had a burping problem the gauge would be reading hot. Mine is too cold. The front heater line is hot. The rear heater lines are lukewarm and the heater not much better.
middlecalf
SILVER Star
What’s the temp of the rear part of the block and head, if you have an IR temp sensor?
So, you're concerned that it only took 3 gallons?
It sounds like it never really got hot. Earlier you mentioned testing the thermostat in boiling water, did you get the temp that it opened at? and if you're already going and popping the cap (I always avoid) stick a thermometer in that and see if it's hot enough to know the thermostat opened (infrared on the outside is for sure safer than popping the cap while it's hot). Though it should circulate enough even without (there is a bypass if I understand correctly) to burp.
I'm sure mine gets hot enough in a 10 minute drive in summer, but I never drive it in winter anymore (no top) and have no idea what kinda weather you have, if it's cold enough, with the fan always going (mine has no clutch), wouldn't be surprised if you really gotta try to get it warm enough.
Maybe also try parking on a steep hill (radiator uphill) or jack up the front to make the radiator the high point of the system, run it a bit, check it again. Air bubble should make it way to the high point.
Thank you. Always so happy with this forum. Still don’t know why it’s running cool. I know it takes between 4 and 5 gallons so 3 is not enough. Wondering if I have to drain the radiator AND block. Wondering if I have restricted flow in the heater lines. I bought an $18 infrared thermometer and am going to try again tonight to get it over 120 degrees. Thats my guess from using my finger. If it’s not getting hotter than that 4 miles of 30mph driving then we have a problem.
I did all that with just the block drain. Will try again tonight.I put something pretty similar to this on the heater hose from the head to the heater core:
Dorman 47152 Dorman Radiator Flush Tee Fittings | Summit Racing
Free Shipping - Dorman Radiator Flush Tee Fittings with qualifying orders of $109. Shop Coolant Flush Fittings at Summit Racing.
First empty, drain under the radiator and under the block, to remove all the old antifreeze.
To flush, hook a garden hose to it and run with the radiator cap off. It's going to constantly add water, so it shouldn't get hot enough to open the thermostat, but run enough water through it to eventually end up with only clean water in the system. You're really only putting in enough water to remove old antifreeze or any other water soluble contaminates. At this stage it's pretty much just water that's running through it and shouldn't need to worry about catching and disposal.
Then open the drains again and empty the water, you don't want the minerals in tap water constantly near boiling in the system.
Refill 50/50 antifreeze and distilled water, or the premixed stuff. Leave the cap off that "T"'s garden hose connector until water comes out or the radiator is totally full, maybe fill some from there once the radiator is full. The air pocket that would typically need "burping" is going to come out this while filling.
And if your in Idaho or Connecticut doing this in January, don't leave it with water only....
And remember that antifreeze lubricates the water pump, don't be running it alot with that.
AussieHJCruza
Supporting Vendor
- Joined
- Jul 8, 2013
- Threads
- 64
- Messages
- 2,977
- Location
- New South Wales, Australia
- Website
- www.completecruisers.com.au
Yes, you need to drain the block as well as the radiator.
Thermostat should open around 180 degrees, I think?
And 4 miles of driving 30 mph isn't much, if your in Connecticut (your profile) with the ambient temperature in January, I'm thinking it's going to take more than that. Drive it until the heater tries to burn your leg.
And, the block probably holds about a gallon, at least.
But really, I think the problem it your too detailed and worrying too much. Most people with cooling problems are from overheating, which is what happens when things are blocked, and sometimes it's inside the block or head (rust or stop leak, or some other crap) and they have major issues. Sounds like your actually doing just fine, put in 3 gallons or antifreeze and top if off with water (distilled). If it's not overheating, you're good. If it's not getting hot enough, put a sheet of cardboard between the radiator and the grill.
yes, I am worrying. It started with no heat in the cabin. I am on my third Thermostat and finally things are looking like they should with the needle moving past C in the first mile and reaching the first tick mark. The Napa thermostat, and the Gates thermostat were both wrong, too short, and with a poor upper seal they let coolant through the upper thermostat housing and everything runs cool. Now, with the right thermostat, gasket and seal (Toyota brand from ccot) I am still working on solving the heater. The lines to the front heater are hot, the valve is open, but still insufficient heat. I’ve been told that FJ40’s have super heat when it’s all working properly. I’m reading on these forums that I need to vacuum out my heater core, maybe lube the bearings and check the ground connections. Will report back. Photo is Gates vs Toyota thermostats.
RevISK
SILVER Star
I ran into a similar issue in where I simply wasn’t able to add more that 2.5-3 gallons after I drained everything. The block took a few go’s as the flush would run clear then some internal gunk would show up and it’d be all nasty again. I probably did 8 flushes and still wasn’t at the 4 gallon mark.
finally, the return hose from my oil cooler started leaking prompting a radiator removal to access.
From that low point I got what seemed like pounds of scale. Also, flushing my radiator in hand revealed more junk that didn’t get flushed before.
I am now able to put almost 5 gallons in and my cooling system seems very efficient in that I’ve yet to see the needle go passed the second mark (once fully burped that is. Had it spike and knew I had an air bubble but also a working gauge).
So, you probably still have a fair amount of gunk in your system preventing a full drain.
finally, the return hose from my oil cooler started leaking prompting a radiator removal to access.
From that low point I got what seemed like pounds of scale. Also, flushing my radiator in hand revealed more junk that didn’t get flushed before.
I am now able to put almost 5 gallons in and my cooling system seems very efficient in that I’ve yet to see the needle go passed the second mark (once fully burped that is. Had it spike and knew I had an air bubble but also a working gauge).
So, you probably still have a fair amount of gunk in your system preventing a full drain.
Green Bean
SILVER Star
When I did a flush I used one of these with good results. https://www.amazon.com/gp/product/B000F5ECRW/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
It was a little startling to see the amount of crud that came out.
I also used this stuff to try and clean everything out. https://www.amazon.com/gp/product/B00JJ1FB28/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
The final step was opening up the engine drain plug which was clogged. Had to do a Roto Rooter-type of procedure to get things flowing. Then replaced with new OEM cock.
It was a little startling to see the amount of crud that came out.
I also used this stuff to try and clean everything out. https://www.amazon.com/gp/product/B00JJ1FB28/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
The final step was opening up the engine drain plug which was clogged. Had to do a Roto Rooter-type of procedure to get things flowing. Then replaced with new OEM cock.
When I had the top on, I never remember it being particularly warm.
Now that I have the top off, it just burns my leg (just the right one). And this is after removing the rear heater.
I did flush my system, filled it up with vinegar (light acid) and drove it around for 20/30 minutes. (ya, it smelled). Then with a garden hose in the "T" I mentioned earlier flushed the vinegar out.
A couple weeks later I started noticing little bits of water under it and doing a pressure test found the seams of the radiator leaking under pressure. So, be careful of the repercussions of removing "crud", that crud might be keeping the whole thing working. At some point, there's only so clean the water jackets inside the engine ever need to be and trying to get them cleaner is more likely to break stuff than lead to any benefit. Antifreeze does need to be replaced periodically, not only does it prevent water from boiling but also lubricates the water pump. But if it's not overheating, it's working.
RevISK
SILVER Star
Another thing to consider is that vinegar needs to be neutralized with a base like baking soda. Otherwise, it’ll keep on eating.
It’s 21degrees right now in Connecticut but they’re calling for warm weather next week. My antifreeze is nice and pink and after a mile of driving the needle will hits the first tick after C but that’s it, never goes higher. A few minutes ago I found out why the front heater wasn’t working. Photo of old wasp nest attached. Removed the nest, vacuumed and put some pbblaster on the motor and it’s no longer seized. I am getting fan up front when I pull out two stops. Nothing on the first stop. My friend says he gets low fan on the first stop and high fan on the second. But I thought I read somewhere that one pull controls the rear heater and two stops the front fan. I know this is basic stuff for all of you but this is still my first month with an FJ or taking apart any vehicle.
pb4ugo
SILVER Star
The 1st notch is low, the 2nd is high. Depending on yrs the 2nd notch turns on the rear heater too. Your low speed may be a problem with the resistor on the fan.
You can remove the 2 screws that hold the plastic duct under the dash on the pass side and remove it. This will give access thru the air inlet to the heater core, from there you can vacuum the debris laying on top of the core.
You can remove the 2 screws that hold the plastic duct under the dash on the pass side and remove it. This will give access thru the air inlet to the heater core, from there you can vacuum the debris laying on top of the core.
Does anybody know where I can buy that resistor for a 1976 FJ40? I’m assuming nobody makes them anymore?
