how to flush radiator

I am having an overheat. problem here is the thing i let my dad take my jeep for the day and he was sitting in traffic not watching the heat gage and it over heated for the first time and blew the bottom hose off. the hose was going bad anyway. i replaced the head gasket and it never ran the same it over heats all the time i can controll it somewhat but whenever i get on it it over heats. I flushed my radiator out and it was spitting out what looked like charcoal but it was hard i could break it into pieaces though it left an oily residue in my hand is that a clogged radiator if so how do i flush it. thank you.

I have a Prestone flush kit installed on my heater hose. Get the cleaner that you have to drive with it for 5 -6 hours. Follow the directions. You might want to consider going to a 3-core radiator from GDI along with a new water pump as well.

The upgrades I have are:

3-core radiator
Flowkooler water pump
Turbo City High Flow thermostat housing
Robertshaw 180 degree thermostat
Heavy duty fan clutch (Although debating going to a flexalite 100 electric fan)

I never approach 220 even with the A/C on!

I have a Prestone flush kit installed on my heater hose. Get the cleaner that you have to drive with it for 5 -6 hours. Follow the directions. You might want to consider going to a 3-core radiator from GDI along with a new water pump as well.

The upgrades I have are:

3-core radiator
Flowkooler water pump
Turbo City High Flow thermostat housing
Robertshaw 180 degree thermostat
Heavy duty fan clutch (Although debating going to a flexalite 100 electric fan)

I never approach 220 even with the A/C on!
I have and electric fan on the empty side of the radiator it doesn't seem to make a dent when i turn in on. When i got to school this morning it was at 260 degrees. how easy is it for my head to warp.

First off - dont believe the quage all the time! I was showing running into the red zone alot after I did the upgrades. But I could touch the hoses and take off my radiator cap - at 260 degrees - no way would I be able to do that! A $14 sending unit solved that problem. However, do NOt continue to drive if it is truly hot because you can and eventually will blow out a head gasket. Also, the heads on a I6 arent aluminum - they are cast iron so they will take alot of abuse. You need to find out why your running so hot. If you have the closed system - convert to the open system, total cost around $250 if you do your own labor. Check your water pump, your thermostat might be stuck closed (Check the upper hose - if it is cooler then the rest then you know you have a stuck thermostat)

As far as the the "charcoal" stuff you flushed out - I havent the foggiest idea what it could be. I would go ahead and flush it again just to make sure you got it all out. I would go so far as to pull the engine block plugs to flush out any gunk that might be lingering inside the block. Worse comes to worse, I would pull everythin..the housing, the radiator, the water pump and make sure you flush the block out well! Also I would replace your fan clutch if you have alot of miles.

First off - dont believe the quage all the time! I was showing running into the red zone alot after I did the upgrades. But I could touch the hoses and take off my radiator cap - at 260 degrees - no way would I be able to do that! A $14 sending unit solved that problem. However, do NOt continue to drive if it is truly hot because you can and eventually will blow out a head gasket. Also, the heads on a I6 arent aluminum - they are cast iron so they will take alot of abuse. You need to find out why your running so hot. If you have the closed system - convert to the open system, total cost around $250 if you do your own labor. Check your water pump, your thermostat might be stuck closed (Check the upper hose - if it is cooler then the rest then you know you have a stuck thermostat)

As far as the the "charcoal" stuff you flushed out - I havent the foggiest idea what it could be. I would go ahead and flush it again just to make sure you got it all out. I would go so far as to pull the engine block plugs to flush out any gunk that might be lingering inside the block. Worse comes to worse, I would pull everythin..the housing, the radiator, the water pump and make sure you flush the block out well! Also I would replace your fan clutch if you have alot of miles.


Thanks po pilot i have a three day weekend coming up and i plan on taring the water pump out and checking the flow on the radiator is there any way to check flow on a radiator if you don't have a flow tester. is it possible that i could be over heating because i am running a 160 because i think the auto part store accidently gave me a 160. i think i found the old thermo package and it said 160 is it possible it is not holding the water in the block long enough to cool it.

You can check the flow rather easily. With the engine running and at operating temps - grab the upper hose and squeeze - make sure your wearing gloves! You should feel pressure build on the engine side of the blockage. If not your pump is weak or bad. Also if it makes noise or if there is play in the pulley or if there is coolant seeping from the weep hole. All bad signs. I say just replace it if you are doing the other changes - the radiator needs to come out anyway during the water pump swap.

Id chunk the radiator and get the 3-core.

Also I wouldnt recommend running a stat below 180 degrees - thats what Im running and everything is just fine. A balnaced stat helps keep the coolant flowing just right - I use a Robert Shaw. No problems yet!

I had a simular problem with mine this summer. I ended up getting the prestone 'super clean', it's like the reular flush only you leave it in for several days (until you get 5 hours of driving time). these freed up a lot of debris and a dark jell that looked like a previous owner had used 'bars-leak' or the like, anyway I found it did a better job than the other flushing chemicals that go for shorter times.

btw- anybody know how to avoid the trapped air in the top radiator hose? so far I've got most of it out byletting the engine get hot and having some of it 'burp' out as the air expanded with heat. the uper radiator is IMO a bad design as the hot water cant flow up to the top of the radiator when you shut off. I've seen my temp climb 10-15 degrees after the motor is shut off

Capt - you have the open or closed system?

I had a simular problem with mine this summer. I ended up getting the prestone 'super clean', it's like the reular flush only you leave it in for several days (until you get 5 hours of driving time). these freed up a lot of debris and a dark jell that looked like a previous owner had used 'bars-leak' or the like, anyway I found it did a better job than the other flushing chemicals that go for shorter times.

btw- anybody know how to avoid the trapped air in the top radiator hose? so far I've got most of it out byletting the engine get hot and having some of it 'burp' out as the air expanded with heat. the uper radiator is IMO a bad design as the hot water cant flow up to the top of the radiator when you shut off. I've seen my temp climb 10-15 degrees after the motor is shut off

Capt. In my repair manual it says to remove the top heater hose and fill until it burps out the air i don't know if this helped because my jeep still was spitting air out but it seems like it worked well with filling the system. I would buy that super clean from pestone but i can't drive my jeep for more than a 30 min. with out it overheating somthing is really wrong i am going to take out my water pump this coming up weekend and see if it is still good. But thanks for the imput i am going to drop my radiator is there any way i could check the flow with the radiator out.

I have the closed system. for now anyway, I hate it, I will be replacing it asap. I'm going with a 3 core, and I'm going to go with electric fans. I think if I go to the lower profile electric fans I can re-route that upper hose so it's not a air-trap.

someone gave me a tip on getting the air out that seems to have worked. first you do everything you can to avoid getting the air in.
(fill it with the top hose disconected, have someone hold their hand over the thermostat housing when it fills that far, then close the bottle when it is ful, then pour coolant into the hose unitl it's full, cover it with your hand until you're close to the housing with it, then remove hands and try to jam it onto the houseing as fast as possible before all the coolent runs out. what a pain in the a$$).

anyway after you go through that whole circus, park it on a hill (front down), the steeper the better, squease the hose and try to work as much of the air as you can back into the engine, then remove the temp guage sensor from the rear of the head and let the air out.

also I think I may have found part of my overheat problem this summer, while working on another issue this weekend I had the snap-on reader hooked up, I noticed I was getting a constant reading of 132 degrees on engine temp, even after the guage came up to 200. the book says the ecu makes adjustments in timming and mixture to help control the temp (not sure how that would work but I'm no expert and thats what the book says). if it can make adjustments that effect the temp, and it constantly thinks the engine is cold then maybe that had something to do with my over-heat problem.

so anyway I figure it's the sensor and hook a tester up to it. I took a cold reading, and was going to warm it up and take a hot reading to see if they changed, but after I plugged it back in the reader gave me a lower temp than before. after start up you could watch the temp rise on the reader. it must've just been a bad conection at the sensor, at least thats the only thing that makes sense to me.

after that I unhooked and cleaned most of the sensor conections and the jeep runs noticabley smoother now.

zee, it sounds like you're having the exact same problem I had, I removed the thermostat, while using the flush solution (gave me an extra 20 minutes of drive time in the city and 30 on the hwy) and left it in for most of a week) the whole process was a huge pain but it seems to have worked for minimal $$. also when flushing out the system (with thermostat removed) I unhooked the upper hose from the radiato and hooked my garden hose to it. this flushed it backwards through the radiator. and I ran a small hose into the radiator and siphoned from the bottom as water ran out the top, this hose picked up a lot of debris.
like I said, it was a pain but since I had no cash to pay anyone to work on it this summer it was worth it.

Greatings im new to the forum hope im welcome

Not really. Resurrecting a 7 year old thread and attempting to hide advertising in your smiley = ban. Goodbye.

Just a few tips I've picked up. First, use a 1/2 water 1/2 vinigar solution to flush it. Put the solution in and run the engine for fifteen minutes, flush and replace with normal fluids. I got that tip from Horsepower tv. I also know that people in the circle track world use restrictor plugs to SLOW the flow of coolant thereby allowing the fluids to reside in the radiator for a longer period of time, there is a better heat transfer that way. I have also seen an inline radiator valve made by a guy in canada, he used a ball joint and some fittings to allow him to adjust the flow of coolant, summer vs winter etc. so he could keep it cool in summer (I wouldnt think he'd need that in Freakin Canada...) but open it to noemal in winter. See GOoJeep Web sight for the pics and details. DRIVE IT LIKE YOU STOLE IT !!!!!!!!

I was just thinking, you said you're over heating, you can open your radiator cap then turn on your car and wait to see if your thermostat opens at all to let fluid run through. I believe that your thermostat can even open partially etc. You can change your water pump. Those arent too costly. Your electric fan might be malfunctioning, but if you're moving and it still over heats, that wouldn't be a factor. How's your fluid levals, meybe you have a leak. Good luck. Drive It Like You Stole It!!!