As long as you still run the engine at temp for about 10 minutes to make sure the air is purged you'll be fine.
Radiator replacement
- Thread starter Flivver250
- Start date
As long as you still run the engine at temp for about 10 minutes to make sure the air is purged you'll be fine.
You can't minimize air being introduced into the system. Air has to be in the system as the coolant drains out. Once the coolant is out less any residual still in the block, the system is full of air. You displace the air as you introduce coolant. The only thing you can try to control is how much air gets displaced.
There should be fluid at all times in the reservoir. The level will go up and down depending on the heat cycle so take a look at it a few times to make sure it doesn't go too high or low before calling it good. If it does go too high when hot you probably need to replace the radiator cap.
The cap was also replaced. I will definitely keep an eye on the reservoir from now on. Well I probably didn’t need to replace any of it as it was more of a user error but I guess it’s good to have a refreshed system with all new parts and a complete drain and flush and proper coolant added. God knows what kind of mix of fluids was in there.
One thing I did notice is some sand and dirt got into the tubes and thermostat housing. Does off roading through water puddles and things that may splash dirt and mud get into the radiator and that’s how it’s introduced into the system? Just curious for next time off road, it may sway me not to make a huge splash
The cap was also replaced. I will definitely keep an eye on the reservoir from now on. Well I probably didn’t need to replace any of it as it was more of a user error but I guess it’s good to have a refreshed system with all new parts and a complete drain and flush and proper coolant added. God knows what kind of mix of fluids was in there.
One thing I did notice is some sand and dirt got into the tubes and thermostat housing. Does off roading through water puddles and things that may splash dirt and mud get into the radiator and that’s how it’s introduced into the system? Just curious for next time off road, it may sway me not to make a huge splash
I've never had a problem with the radiator fluid getting contaminated. Be careful of your breather lines for the diff, trans, and transfer case. And you don't want to expose your electrical connections to too much pressure.
What size hole is recommended for the stant super stat? I am installing the stant kit with the thermostat, radiator cap and temperature sensor. I would assume draining the block is a good idea to replace as much of the coolant as possible? Any problems or concerns on removing the plug on the block?
1/8” hole. I would drain the block. There was a fair amount of fluid that drained from it. You will need an 8mm plug remover. I ordered from amazon and it was $3. It was hard to reach/find but not overly difficult to remove. I put thread sealant on anything that could possibly leak, including the drain plug.
The "hill trick" does work. You still need to get the engine up to temp and open the thermostat. By making the radiator the highest point in the system the air will want to move there. It it that simple. No tricks, just air is lighter than water. Is it always 100%? No. But on the Nissan that I used it on it was the only way to get an air pocket out without pulling a head bolt. The dealership wrench told me this is how they do it. And you run the heater it is to verify there are no air pockets there either. If I wasn't clear enough earlier then please accept my apology. I have done it this way ever since and have never had an airpocket issue with well over a dozen different vehicles.
I believe in this thought process about air. I work in cardiac surgery and we do similar tricks to get air out of the heart to prevent an air embolus from causing a stroke. Air wants to move to the highest point.
I found it behind the rear precat. Looks like a bear to reach. Were you able to get a ratchet in there without removing the cats?
Yes. I used a 4” extension on the ratchet. Or 6”. Either way you need an extension.
Edit: I just checked and I used a 3” extension
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Thanks for your help. I had a previously ground down extension so I touched it up to 8mm, stuck another 3 inch and a 1/2 adapter on it. I put my 1/2 rachet on it and brought it right out between the cats. I just put that exhaust on and I sure didn’t want to take it off. I’ll take your advise on that sealer also. Thanks again.
My buddy's TJ has the heater core bypassed due to a leak. Main reason is, replacing the core is an annoying task. I had to replace my ac evaporator so I put in a new core at the same time. Told him to do the same. Having the core increases your cooling system's capacity.
While total capacity will take longer to get to temp and stabilize larger spikes, it won't effect your systems ability to maintain the engine temp, within reason (unless you're additionally exhausting that heat into the cabin of course...).
All other parts being equal, except one system with a larger capacity, the radiator is the dictating factor and there will be no difference.
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For fuck sake Blane turn the heater on to verify no air pockets there. Otherwise you dont know weather the heater core is air locked. If you dont understand this then go to your nearest ocean, lake, pond, or stream and hopefully you will notice that the air is ABOVE the water. The water is BELOW the air. This appears to be understood by most every preschool kid. Maybe find one and they can explain it to you. Good luck. Out.
@Goatman
In a Jeep TJ the coolant flows through the heater core whenever the engine is running no matter how the heater controls are set. The controls direct the flow of air, not the flow of coolant. It therefore makes absolutely no difference whether one "turns on the heater to verify no air pockets" or not.
@toximus
I bypassed my heater core last July due to a leak but didn't have the replacement heater core installed until February. That gave me ample opportunity to observe temperatures with the heater core in and out the system. I can confirm that the absence of a heater core in the system did not have any adverse effect on total cooling even during a 10-day heat wave of 110*+ temperatures. My temperature gauge was typically at 210* before the heater core leak, showed hotter between discovery of the leak and the heater core bypass, returned to the typical 210* after the bypass, and has remained at 210* since the heater core replacement. Even though most TJ's have a dumbed down gauge that does not show small changes in coolant temperature, the fact that the gauge remained relatively constant is an indicator that any difference in coolant temperatures with the heater core in and out were also small enough not to be a concern.
I'm considering the addition of a "summer/winter" valve to bypass the heater core in warm weather so the A/C doesn't have to work as hard. One of the things I noticed last summer with the heater core bypassed was the much colder air from the dash vents.
In a Jeep TJ the coolant flows through the heater core whenever the engine is running no matter how the heater controls are set. The controls direct the flow of air, not the flow of coolant. It therefore makes absolutely no difference whether one "turns on the heater to verify no air pockets" or not.
@toximus
I bypassed my heater core last July due to a leak but didn't have the replacement heater core installed until February. That gave me ample opportunity to observe temperatures with the heater core in and out the system. I can confirm that the absence of a heater core in the system did not have any adverse effect on total cooling even during a 10-day heat wave of 110*+ temperatures. My temperature gauge was typically at 210* before the heater core leak, showed hotter between discovery of the leak and the heater core bypass, returned to the typical 210* after the bypass, and has remained at 210* since the heater core replacement. Even though most TJ's have a dumbed down gauge that does not show small changes in coolant temperature, the fact that the gauge remained relatively constant is an indicator that any difference in coolant temperatures with the heater core in and out were also small enough not to be a concern.
I'm considering the addition of a "summer/winter" valve to bypass the heater core in warm weather so the A/C doesn't have to work as hard. One of the things I noticed last summer with the heater core bypassed was the much colder air from the dash vents.
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It is definitely easier before you install the radiator. I used a 1/4" tap to make threads. No drilling necessary. It makes bolting up the shroud super easy.
I was able to impact drive the top passenger side bolt. Gonna hope I can do the same driver side but may be difficult. If I can get those two then I’m ok with it.
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