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Wallet flush makes sense?

I took my son’s 2009 Sonata in for oil change and transmission drain-and-fill. (He’s busy working. I’m retired and have time, and I offer do do this kind of errand for my kids.) I went to a quicky lube place (few choices on a Sunday, and don’t worry – I did not ask them for directions and I did check that there was actually new oil in the engine).

The shop did not offer drain-and-fill. They do only flush and fill…for $99!! A quick telephone consult with my son, and we took a pass.

Looking on-line for how to do it myself (do radiators have petcocks any more, or will I have to loosen the lower hose?), I came across one video for a Hyundai that says I might have to remove an air dam under the front of the engine – lots of screws and clips. Whoa, pardner! If that’s the case, maybe a (trustworthy) shop would be right to do flush instead of drain-and-fill. R&I on the air dam could be a lot of time = $$$.

Any thoughts? Could the flush be cheaper on some cars; and on the '09 Sonata would I have to R&I the air dam?

Are you referring to a transmission flush? Or an engine oil flush? Or a coolant flush?

Transmission flush, instead of transmission drain-and-fill.

Here’s the machine I use for a coolant flush.

You just connect between the upper radiator hose/radiator, fill it with fresh coolant, turn it on, and it exchanges all the coolant.

How easy is that?


You said transmission but you asked if radiators had petcocks, which is it that you are asking about. Maybe your son can find an independent shop to do all of the things this vehicle might have on it’s schedule.

2.4 L 4 banger or 3.3 L 6 banger engine?

Jeez, what a dolt I am. Just now I had to work to remember what my son had asked for. I remember alerting the shop that the owner’s manual specified ethylene glycol based anti-freeze, so I meant coolant, not transmission. But I also (in confusion) said to the shop “drop the pan and drain and refill; not flush”, so I think they were quoting me for transmission flush.

Sorry. Please reframe the inquiry for exchanging coolant:

  1. Could it be cheaper on some cars to flush coolant from the top than to drain and refill (because of the effort in getting to the bottom of the radiator)? (Tester’s reply indicates “Yes.”)

  2. Would that be the case for the '09 Sonata? (“Yes” would imply that I should not do this at home.)

wallet flush means you think the service is not required? anyway, most cars have a plastic pan under the motor that you remove to even reach the radiator drain. a coolant drain/fill is easily 99 at a shop. a trans fluid exchange is more than that. a 8yr old car could use both services.

No an issue if using a lift

“wallet flush means you think the service is not required?” – Not at all. Coolant gets changed every couple of years, and transmission fluid every 30K miles or so, based on recommendations on this site. General opinion on this site (10 years of lurking) is transmission flush = wallet flush, and drain-and-refill is all you need. (Some experts here disagree.) I probably got confused by the word “flush” for coolant.

“anyway, most cars have a plastic pan under the motor that you remove to even reach the radiator drain” – That’s Question 2.

“coolant drain/fill is easily 99 at a shop” – I guess. That’s what makes DIY attractive … except for Question 2.

“8yr old car could use both services.” – On schedule.

" ‘because of the effort in getting to the bottom of the radiator’ No an issue if using a lift" – No lift at home :>) I was talking about having to remove an air dam beneath the radiator. E.g.,

I just pull the hose. Even with the need to remove the splash panel (air dam), I still find it easier. II recommend NOT using a flush in any portion of a good-running engine or tranny. Simply drain the old fluid and replace with fresh fluid.

IMHO you did the right thing in “passing”. But I would recommend avoiding these lube shops entirely in the future. Their business model is not conducive to quality work. We get countless people who write in with serious problems caused by these places. I personally have witnessed some scary stuff at quickie-lubes.

TSMB – If I go under the car I’ll likely find that you are right – easier to disconnect the hose. But the splash panel removal and installation shown in that video is more than I would want to take on. And coolant exchange can wait until car gets to next oil change interval and I can take it to my trusted independent.

Avoid quick lubes? Generally good advice, and I did follow consensus here not even to ask them for directions. But time constraints limited my options, so I checked the “new” oil and hoped that they did not mangle the drain plug. And we kept the receipt :>)

If your transmission has a drain plug, you can drain and refill it yourself. It’s a lot like doing your own oil change, except there probably isn’t a filter to change. I caution whether it’s a good idea to do it yourself though. It’s easy to overfill the transmission or use the wrong kind of fluid, and you seem to be getting bad information on how to do it.

If draining and refilling my transmission involved disconnecting a line from the radiator, I’d hire someone to do it for me. It’s far too easy to mess up that job and end up with a leaking connection between the line and the radiator if you over-tighten it, under-tighten it, cross-thread it, or misuse gasket tape.

Maybe you should find an independent mechanic who is willing to drain and refill your transmission for around $40-60.

If the owner’s manual calls for a simple drain and refill, that’s all it needs. Some people obsess about the fact that a simple drain and refill doesn’t replace all the fluid, but if you don’t suffer from OCD, a drain and refill is all you need.

We’re talking about coolant drain and refill (or flush from top).

I goofed when I talked about “drop the pan”. For transmission fluid change I do go to my trusted independent mechanic. Also for coolant change because it’s more convenient to combine that with other service than to do it in my carport. Storing the old liquid and then making a trip to County recycle center to get rid of it is a hassle.

In that case, there are many shops that will drain and refill your cooling system rather than flush it, and personally, I refuse to let any mechanic flush my engine with chemicals. I’d rather not take a chance that they’ll mess it up and damage my head gasket.

I haven’t done this on my current car, but I’ve been thinking about doing it recently, so here is my advice:

If you feel a need to flush your cooling system, buy a flush-and-fill kit from an auto parts store, install it, and do it yourself with water. The only downside to doing this is that you’re using tap water, so you’re going to want to get as much of the tap water out as you can before refilling the cooling system.

Personally, I prefer to refill the cooling system with ready-mixed coolant rather than fiddle with distilled water and mixing it manually. It costs a little more, but I think it’s worth it.

If you can’t find an independent mechanic who is willing to drain and refill the system, the national chain shops I’ve used will do it for you, including Firestone and Goodyear. I only caution you that their franchises aren’t always trustworthy, but their corporate-owned stores are more reliable because they’re usually held accountable, at least in my experience.

Here are the FACTS about maintaining the cooling system.


I can’t say for a Hyundai, but on my family fleet of GM and Chrysler vehicles I drain and refill most of the coolant from the top!

I use a length of clear plastic tubing (about 3/16" i/s diameter I would guess without a trip out to my garage). I run it straight down through the cap on an end tank of the radiator. I will go to the bottom on my cars.

Next a use a plastic syringe (about $3 @ Wal-Mart auto dept.). with the loose end of the tubing nears the ground I insert the syringe into the tubing and draw up enough coolant to almost get to the syringe.

Then holding the syringe at the opening of an empty gallon jug (transparent/translucent is best) I simultaneously remove the syringe from the tubing and insert it into the jug. A siphon begins and takes a few minutes to fill the jug.

When it nears overflowing, I lift the tubing enough to break the siphon and cap the jug. I ready another jug and repeat the process until I have as much coolant out as I can.

You can also do this to the expansion tank, but it’s so easy to remove the tanks on my cars I usually do that and clean them inside and out.

Finally, I refill and bleed the system as specified by the manufacturer.

This method doesn’t get all the coolant out (surprisingly, according to my system specs it does remove most of the coolant), but it’s so easy (almost fun), cheap, and neat that I do it regularly (every year or two) enough that the coolant never gets dirty or exhausted.

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Sorry for not reading all the responses but not only do some radiators not have petcocks, some don’t even have radiator caps. You drain them by pulling off the lower hose and you fill them by pouring the coolant into the upper hose. Thats one of the reasons I just hired it done last time-BUT NOT AT A QUICK LUBE.

This thread should be titled ’ Flush or Drain and refill '. Vehicle service is not a wallet flush.

Why? You saw “Wallet Flush” so you clicked on it to find out how to finally get your wallet flushed out? :smile:

Where’s the harm? Authors are responsible for the wording of their discussions. It looks like it’s going well to me! :wink:

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