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Hey guys. My car, i just bought few months back, is at that mileage point where i need to do some maintenance stuff to it and had couple quick questions. It's a 2007 hyundai Elantra by the way. With all cars that I've owned in the past I've always done a back flush for the radiator system instead of the normal flush,where as you  hook the water hose to the radiator cap top and flushing it that way. But now Im wondering if I should be doing a normal Radiator flush instead.
 My train of though in this is that if the point of entry for the water is through the Heater Core intake hose, as it is in a back flush, then wouldn't that mean no water is getting pushed through the engine area, where the water pump is?? In a back flush doesn't the water travel through the Heater core intake hose, through the heater core, into the Heater core outtake hose then back through the bottom of the engine into the lower radiator Hose then spewing out the top of the Radiator cap thus by passing the top Radiator hose that flows through the thermostat area where as if you do a normal radiator flush where the first point of entry in through the Radiator cap?? I'm Thinking if that's the case wouldn't it be better to do the normal radiator flush, beginning the process at the Radiator cap area? I turn the water on, then start the car then once the thermostat opens up water would freely flow through the thermostat, into the engine area with the water pump into the heater core intake hose, then the Heater core...Well, you get the idea. Just want to know if my thinking on this is correct and which one to do.
 Second(Far quicker question) I'm gong to be checking the brake pads and Rotors. I already pulled off one tire last week to get a good look at the timing belt and saw the rotors had little rust on them and am going to use the little bit of sand paper to get it off. What Grit sand paper to use?? I'll be wearing a breathing mask to keep from breathing in the brake junk that comes off. Any advice on these task would be received with much thanks.  

first..  the thermostat really needs to come out and be replaced when you service the cooling system...

This is usually done at the same time the water pump is replaced with the timing belt.. if it has a timing belt..  i would have to look it up...  the hyundai dealers have most of the heavy service wrapped up around here..  i almost never see one..

please DO NOT USE ANY KIND of radiator flush..   you have mostly an aluminum motor.. aluminum radiator, steel head gaskets..   you really DO NOT want to put any kind of acid into the system...

it will take 30 gallons of water or more to wash it out .. then you have to neutralize it.. and wash that out..


if you drive the car around the block twice.. the rust on the rotors will be GONE..

if you wash your car and then let it sit without taking it for a drive to dry off the underside and exposed brakes.. you will have slight rust issues..

one guy down the street parked his car next to the place that watered their lawn twice a week.. the water would blow onto his wheels and spot his rotors...  he was ready to go to war with that building manager..   i almost had him convinced to spray them with WD40..  he was a push over..  that would have been a bad thing to spray on.. i just wanted to test his IQ..  seemed it was about the same as the number of lug nuts on his car..  

you can also check the coolant for acid content..

or

check it with a digital volt meter.. it will measure voltage when its really gone bad..  at that point you have a electro plating company going backwards and removing your aluminum cylinder head cooling passages...  

Don't plan on using any type of radiator flush liquid, just plain water out of the garden hose. I was trying to avoid taking the thermostat out but seems like it would be the best thing to do. Thermostat is only $12 anyway.
looked at the timing belt last weekend when i removed my right front wheel.Timing belt appeared in good shape, like it wasn't changed to long ago. Still want to change it soon so I KNOW when it was changed. Going to wait a bit before i change the water pump. Car is at 88,000 miles right now. I bought it when it was at 95,000. I'll want to fork out money for a new timing belt first.
So what your saying is the best thing to do is remove all hoses: Heater core hoses, top and bottom radiator hose, then thermostat and my Heater core. Spray water into the opening where the thermostat was, and rinse out the engine part that way??  Then check the Heater core separate. Then check the hoses to see if they need to be replace?? I plan on replacing them later on but right now i just want to flush the system and put some new fluid in. Have to use the funds correctly, limited on cash. Or are you saying that i should keep all hoses intact, remove the thermostat then hook the top radiator hose back on and flush the system like you would normally just without the thermostat?? Should I have my car running while doing this??? Is it okay to having it running without the thermostat since the water hose will be pushing fresh water into it constantly??
What will i be neutralizing?? what will i use to neutralize it??  

buy a NEW thermostat and gasket... OEM TEMP.. or an hyundai thermostat and gasket from the dealer parts department..

drain the cooling system...

remove the old thermostat.. reinstall the housing..

leave the drain open...   fill the radiator with a running garden hose... when the engine gets filled.. start it...  let the pump push water around the system until it runs clear from the drain valve...

shut the engine off..   let the system drain... pull the thermostat housing...

i normally use a shop vacuum on blow... or a leaf blower .. i personally will blow into the radiator with my mouth... to expel the water from the block via the open thermostat housing..

install the new thermostat and gasket.. ... close the drain... refill the system,,  i normally fill it really slowly.. as there is on most imported type cars... a rattle valve in the thermostat..  so a TINY amount of air can get past... this allows any air trapped behind the thermostat from building up and creating an air lock ... that would prevent you from completely filling the system and engine damage will result..

i don't have a book on the 2007 model.. i don't know off hand if there is a way to bleed the air out of the system...  

Thanks for your help Wayne on this. I appreciate it a lot.  

Hey wayne, I was checking the info on the autozone site to remove the thermostat so as to prepare for the radiator flush and it has this caution on the info:


NOTE
Removal of the thermostat would have an adverse effect, causing a lowering of cooling efficiency. Do not remove the thermostat, even if the engine tends to overheat.

Now, I know I I'll have the thermostat off only for the radiator flushing, but with this warning should i just leave it on while flushing?? Or, is okay to take it off considering, I'll have fresh water running through it all the time and that I'll be putting back on afterwards?? Need your advice on this.  

the thermostat has to come out for FLUSHING only..

please use a NEW one when you put one back it...

use the OE temp.... don't try to reengineer the system...