Pictured is a commercial radiator pressure tester. They are relatively expensive for the DIY home mechanic. But, there are times when it would be very handy to have a radiator pressure tester for finding leaks leading to coolant loss and possible engine overheating out on the highway. (The photo is from Google images.)
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Signing UpStep 1: My homemade tester
When we had one youngster in college, another in high school, and my wife was working we had four cars in the driveway for a while. We had another child out in her own apartment, but she always brought her car to dad when it needed to be fixed. It was not uncommon for one of these cars to have a mysterious coolant system leak. I made this pressure tester so I could locate and fix such leaks quickly.
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There is no cover underneath so I have a good
Visual..... The leak is coming from one of the
heater hoses that connects to the throttle
Body, those hoses n clamps are all new but
There is still a leak....HELP
I like good practical Instructables that solve real problems and save people trouble and money. Not all that you find here is practical or solves a real problem. I hope you enjoy the site.
It will be good to see pictures of the testers you build. I hope it saves you some trouble and some money.
Here's an idea: Prestone makes a flush kit that installs a permanent T-fitting into your heater hose. It accepts a standard, male-thread garden hose. Install that T-fitting, and you have a permanent access point for flushing and pressure testing.
You could make a pressure-tester by using a solid brass piece with male garden hose threads, and a barb on the other end for inserting into hose. Build your pressure equipment onto that hose, and you've got a pressure tester with an easy access point. Take care, and thanks again.
One thing ... i would want to solder up my own copper t-fitting, even if it cost more. It would be a much more durable solution than the plastic T-fittings. You can get the parts for all of it in the plumbing section of any hardware store ... even have raised lip edges on the t-fitting where it pushes into the hose. You can get a metal cap in the garden hose section. Then make the pressure tester from a *female* garden-hose-threaded brass barb (I got that wrong in the first post), and it would be a very rugged, jeep-worthy solution.
Also, Dorman Auto Parts makes just the plastic T-fittings and caps for less than 1.50 each. The part numbers are:
- 47120 for 3/4" heater hose.
- 47121 for 5/8" heater hose
- 47122 for 1/2" heater hose
But that doesn't include the adapter that allows a male hose end to attach to the male T-fitting. It mostly serves as a replacement or extension for the Prestone flush-n-fill kit (allowing you to use one flush-n-fill kit on more than one car.)
Anyway, I hope this helps someone. And thanks again for sharing your knowledge with us. You've given a lot of us something very good. I've always known a pressure tester would come in handy, but couldn't justify the cost for occasional use.
I am thankful that I have not had a radiator leak problem since the 1980s or early 1990s. I will certainly keep your suggestions in mind for the day when I do.
Your idea is good, but I'd pressurize the circuit on another point that didn't require the cap to be removed. That way I could test the cap for leaks and I'd also make sure the pressure release system works as it should.
Here' s a stupid question, why pressurize at the radiator cap? Why not pressurize at a heater hose at the thermostat bypass? Sure its a little more involved and you might drip a little but it should be able to pressurize anywhere in the system you like, right?
Thank you for your interest and your comment. It sounds like your bicycle pump adaptation should work. Watching the gauge for declining pressure may not be necessary. Sometimes you will hear a hiss or see bubbles. Do not worry. Leaks are of such a nature that you will have another one day, even if you have none now.
I had written a longer comment (my first one here) but when I tried to send it, it burped and lost the whole thing. I should have copied it to the clipboard before I sent it just in case it bombed out. Anyway, in the longer comment, I mentioned how my service manual suggested doing a pressure test, and while searching for a pressure tester, i found your article, and signed up here. This looks like a great website, and has lots of things my wife would be interested in too. When I get some extra time (I have to replace our water heater that just sprung a leak tomorrow) I plan to try the bicycle pump method just for fun (and to be ready next time I have a leak), and I will report the results here, maybe with a photo or two. Until next time....
Sometimes strange things happen to comments here. While offensive comments are often seen and removed by the moderators, comments also disappear all by themselves once in a while, only to reappear days later. Who knows?
I wondered how you found my Instructable on the radiator tester.
This is a great site. I wish they had a category for "workshop." When posting, "life," "home," "ride," and "technical" just do not describe some of my projects; but that is what I need to use. I am not sure it makes a difference, either.
Some of those posting are young high school kids who think pranks are cool and only want better spitwads or stink bombs. I prefer useful how-to information that solves a problem inexpensively. Currently I have 127 things I have posted. Some are better than others. Those I think are significant often do not gather much attention, while something I was almost embarrassed to publish excites thousands. Go figure.
Instructables has a "be nice" policy on comments and most are very kind in their comments or they ask a simple question. Some can be very sarcastic. These usually have posted nothing of their own. Often someone makes a comment to something I posted that expands my idea in a way that makes it even more useful to all of us. I have made several friends here whom I will likely never meet in person. Some of these live on other continents, but we have similar interests.
I hope you continue to enjoy the site and will post some things. Remember most users simply appreciate the honest effort you made, even if they are not likely to use the idea. But, it is great when someone posts a photo of their execution of your idea.
I finally had a chance to try the bicycle pump in the overflow tube idea. Imagine my disappointment when I found out that it wouldn't work. It would have worked, except for one problem. The radiator cap has an inner seal and an outer seal. The inner seal keeps the fluid in the radiator until it gets hot enough to overflow. It is usually set to relieve at somewhere around 15 PSI or a little higher, I think. The outer seal around the rim of the radiator cap is to prevent leakage in or out of the "coolant recovery system" which includes the hose and the coolant reservoir.
I discovered that the outer seal relieves at a much lower pressure than the inner seal. Thus, each time I pumped air into the "coolant recovery system", although some of it would go into the radiator through the center "vacuum return valve", most of it would leak out around the cap with a loud hissing sound. Thus, I could only get around 2 or 3 PSI pressure into the radiator, which didn't register on the pressure gage because the "vacuum return valve" would close at the end of the pump stroke, which would isolate the pump gage from the pressure in the radiator, and the pressure outside of the valve would quickly bleed down through the outer seal.
I only knew that I had gotten pressure into the radiator because when I removed the cap, there was a mild "whoosh" of air coming out. I repeated it a few times to make sure that's what was happening. So, although the pump with built-in gauge might work ok, I need a different location to attach it to the cooling system. I might try cutting a heater hose and installing a "tee" connector in it, with a tire valve on the branch from the tee. If I actually do it, I will post the results here.