Renix burping question

as I have some struggle with temp ups and downs I checkt the t-stat again today.

drilled 2 small holes one at 12 and one at 6 o´clock as someone writes it is good.

I put up the back so the temp sensor is the highest point. I put out the sensor and bottle open.

I started to fill fluid into the bottle and the big radiator hoose until fluid comes out of the sensor hole. I put the sensor back in and filled up the hoose until the fluid comes out of the t-stat housing.

Then I put the hoose back on and started the Jeep. Tha bottle was still open and fluid was at the bottom.

the gauge shows the raising temperature but vary slowly. I did 3000rpm until it goes near 100 degrees. then the fluid comes out of the bottle

How much should be in when engine is warm. And how much when cold.

When I drive the temperature is between the first mark and the half of the gauge.

when i shot off the car the gauge raises to the point on the picture below...:huh:

When I had the closed system I would fill and close it up and run it on a short trip around neighbor hood. Let it cool and while still closed I would then bleed air from sensor on rear of head. Sometimes I would have to do it later in a few days of driving.

I believe the bottle max cold is halfway, should be a marking on it. Without the cap on its gonna overflow when warm, closed system design.

Your first pic is right where it should run, 195f or 90c. Second pic is normal since the airflow and water flow stopped cooling when you turned off motor. As long as it drops back down to first pic temps, you have bled it good enough.

As a sidenote, running around with fuel that low means your not cooling your fuel pump in your gas tank. Fuel pump is cooled by the gas its sitting in. Reguarly running with less than a 1/4 tank will have you replacing a fuel pump. Just in case you didn't know, I didn't on my first non carbureted car.

Try taking off the small heater hose at the thermostat housing and filling the coolant bottle until coolant comes out of the housing. This should get the majority of the air out of the system. If you are still overheating then you may have other issues. Also be sure of your coolant to water ratio, too much coolant and not enough water in the mixture will cause an overheat condition too.

MACH90XJ said:

As a sidenote, running around with fuel that low means your not cooling your fuel pump in your gas tank. Fuel pump is cooled by the gas its sitting in. Reguarly running with less than a 1/4 tank will have you replacing a fuel pump. Just in case you didn't know, I didn't on my first non carbureted car.

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fuel is not low at all! first pic is with running engine, second pic is shut off. at this point the gauges do strange things, Ttemp raises fuel falls down, I have no clue why

Are you saying water is coming out the cap on the pressure bottle ? Then thats when your temps rise ?

Steffen84 said:

fuel is not low at all! first pic is with running engine, second pic is shut off. at this point the gauges do strange things, Ttemp raises fuel falls down, I have no clue why

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I think you have a normal running temp. The fluctuation after you turn key off is normal too. No water flowing, residual heat in block keeps heating the water/antifreeze til you start and get the cooling system flowing again.

Key off, fuel gauge will drop down, normal.

Cap and bottle is the weak link on this system. Keep a spare around, it will fail eventually.

Notice that the 4.0 sits in the engine bay at a slant, i.e., lower in the back than in the front. The RENIX water temperature sender is therefore in a 'low' position. One procedure, (or trick), to "Burp" the water, (distilled water with anti-freeze mixture), out of the removed sender, is to raise the rear of the vehicle in order to insure that the air, and water can 'burp' out of that configured newly highest point of the engine. On the passenger side, stand-by with your fluid mix, and continue to top off the water bottle while watching over the engine to ascertain when the fluid coming out of the removed sender seems to be a steady purge of fluid, i.e., with little, or no air exiting. Also, while standing there next to the bottle, look down inside to see a pipe vertically placed. Just continue to keep the fluid up to the top of that pipe. As others have said, keep an eye on that fluid level, i.e., before starting up in the morning check your water level, and top off as necessary. Might as well check your other fluids too, especially your oil level when it is dead cold, as well as properly, and totally drained down into your oil pan.., btw. Also be careful when replacing the water fluid cap to the bottle. Do not over-tighten, as it can crack, but just snug enough will do. Like already mentioned get a spare bottle. If you can find an OEM one all the better as the after-market ones seem to be sub-standard. There is a Volvo cap that is even superior, but I forget from which model it comes from.

Some years ago the local parts suppliers where selling the Jeep thermostat as a part designed for multiple vehicles (some Chevrolet). It was packaged with a universal gasket, which doesn't work with the 4.0.

If the gasket doesn't look like this, you have the wrong gasket and your system will/may cycle hot-cold and/or normal-cool.


bilder uploaden

gasket is the right one. I bought it from rock auto. I think it was air in the system. but the two holes let the water in the big coolant circle and will effect that the 195 dgree will not be reached when driving around.

The thermostat needs that circulation to move the air up and out of the system, air inhibits coolant flow. And to help avoid pockets of coolant that is too cool and too hot. It is much like a basic mixing valve (mischventil), common in many heating systems.

The top radiator hose is also a high spot that traps air. I squeeze it flat, let it expand and squeeze it flat again maybe 5-6 times and watch the surge tank (Ausgleichsbehälter) for air bubbles. If the top hose is really old and really stiff, squeezing it flat may cause cracks, be careful.

Thanks 8Mud for the German language lesson, lol.., about time! I will try not to confuse my Mischventil, and Ausgleichsbehalter under the hood.

Also there are some after market 'T's that you can install/splice in your top heater hose which have a screw-on cap in which you can either add fluid, or purge air. I think Prestone offers them via parts stores. Previous owner had one in the XJ I have now, and along the way I bought another new one for my spare's-box.., because like anything plastic, in particular, they will become brittle over time. I have found that 'T' useful as a quick check as per any air in the system when I feel like it.

Are you sure your temp gauge sending unit isn't faulty? It happens all the time.

FWIW my 89 the temp gauge never goes above the center point but it does go there, then drop down to the next lower line *tstat opening* then will climb back upto the center line except when crawling off road.

Rinse, repeat....

The way my gauge behaves is the reason almost all modern cars have a dumbed down temperature gauge. They will sit in one spot until the coolant is WAY past that temp or WAY lower than it THEN it will move. It stops people from thinking something is wrong when the gauge behavior is perfectly normal.

firehawk618 said:

Are you sure your temp gauge sending unit isn't faulty? It happens all the time.

FWIW my 89 the temp gauge never goes above the center point but it does go there, then drop down to the next lower line *tstat opening* then will climb back upto the center line except when crawling off road.

Rinse, repeat....

The way my gauge behaves is the reason almost all modern cars have a dumbed down temperature gauge. They will sit in one spot until the coolant is WAY past that temp or WAY lower than it THEN it will move. It stops people from thinking something is wrong when the gauge behavior is perfectly normal.

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since he mentioned other gauges doing wierd things, it probably is not reading correctly.

OP:
under dash grounds ar non existent in an AMC jeep. Bond everything to the stud above the fuse block on the drivers side. Every seperate piece of the dash frame. AMC relied on the mechanical fasterners for grounds, after 20+ years they don't work so well. Since it's all riveted it's far easier to drop self tappers and ground wires than to take it apart.

After that, ground the battery to the inner fender, and replace the ground strap on the motor with a piece of 4ga wire.

Then check the firewall connector and pay attention to the orange/pink wires at the top. And the brown wire at the ignition switch.

do all that and you'll notice your gauges, in fact everything, all work much better and more consistently.

I installed a new CTS and flushed the cooling system. I put a new thermostat in without holes!

So I started to burb like I should, filled with 50/50 mix cap open and idle.

started to go higher revs, about 3000 rpm. than idle again and so on. there are still small bubles coming up from the bottle...Temperature stays at 100 degrees (european) when the car stands while driving around it drops down a bit and goes up again.

Is there any chance air could get into the system?

http://youtu.be/wnFTVG29js8

You get most of the air out by burping the system, getting all the air out can take days of driving. I'd have to add a little coolant maybe once or twice, a couple of days after radiator/cooling system work, as the rest of the air slowly worked it's way out of the system.

My gauge fluctuates from around 80-100, depending if It has been idling (temp. goes up) or running/driving at higher RPM's temperature goes down. Driving at a constant speed the temperature stays about the same after the motor is warmed up Sometimes it gets as high as 110 if I've been idling a long time in a hot day, this is about where my aux electric fan kicks in and the temperature goes down again quick.

You have to remember the temperature gauge sensor is high on the back of the motor, the thermostat is in front. Cooler coolant comes in the motor in the lower front. Takes some time for the thermostat to react.

Below 70 C you have problem, below 60 C you have a real problem, above 105 C you have a problem, above 115 C you have a real problem.

A partially plugged radiator can cause wild fluctuations in the temp. gauge, the coolant in the radiator at lower RPM's flows slowly and gets too cold. At higher RPM's it may overheat because the coolant flow is too slow. You can often tell a plugged radiator because the top radiator hose gets hard as a rock and may even swell when you up the RPM's.

I found this today when I came home and engine shut off.

http://youtu.be/stVfcLxqPsE

When I drive it the temerature goes from 70 to 100 and back to 70 and so on. Is it because of the bottle?

A cracked bottle *usually* allows the pressure in the system to drop. Lower pressure lowers the boiling point, coolant may boil at hot spots inside the motor and cause lower coolant flow. They call it a balanced system, though a very primitive balanced system. if the system is way out of balance odd things can happen. But what almost always happens eventually is, to much coolant boils and causes the bottle to swell and the coolant to geyser out the cap. The cap is a pressure cap with a valve and spring.

*Best guess* is your heater valve and/or heater is plugged and/or your radiator is partially plugged.

The heater hoses, through the heater valve, are a partial bypass for the thermostat. This bypass for the thermostat keeps a more constant temperature at the thermostat and helps it to respond quicker. Cold coolant and hot coolant don't mix well and are slow to equalize temperature.

The heater valve gets really brittle with age and is hard to dismount and remount without breaking it. But I've taken them off and soaked them overnight in a jar full of Vinegar and had them look like new the next morning.

A plugged or partially plugged radiator will often cause the top radiator hose to swell and get really hard, Generally speaking the pump sucks better than it pushes. The pump can suck so hard it partially flattens the bottom radiator hose at higher RPMs. that is why they put the spring inside the lower radiator hose.

Bryan C. said:

Try taking off the small heater hose at the thermostat housing and filling the coolant bottle until coolant comes out of the housing. This should get the majority of the air out of the system.

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In my experience with multiple renix rigs over 12 the last years....... That

"Try taking off the small heater hose at the thermostat housing and filling the coolant bottle until coolant comes out of the housing. "

is the only way anyone will ever get the radiator on a renix closed system filled to the top with coolant. All the other methods fail to ever fill the radiator more than 50% even after standing on your head and making sacrifices to Buddha (LOL) or boiling the system over driving it for months praying for mercy from mount Olympus as you top off the bottle in small amounts , unless you add a filler neck to the upper hose and use it. I have confirmed this with IR gauges and multiple Renix jeeps with all new cooling system hardware.

That is the easiest, and fast way I have found. Great suggestion!!!!