How Do I Pressure Test Radiator Hoses To Check For Leaks When I Can't Turn On The Bike

[Corey]

I am replacing all of the radiator hoses on my 5th Gen. In order to replace the hoses around the thermostat I had to take off the airbox and throttle bodies (which involved disconnecting the throttle cables).

After I change the hoses I would like to pressure test the system to make sure I don't have any leaks. I would like to do this before I put the throttle bodies and airbox back on 1). because it is easier to see if you have any leaks, because nothing is blocking your view and 2). it will save me from having to pull them again if I do have a leak.

My question is this...

How do I pressure test the system with the throttle bodies disconnected?

More specifically, how do I get the system fully filled with coolant without starting the engine and running the water pump?

And how do I "blip the throttle" 3-4 times per the service manual instruction to bleed the air out of the system when the throttle bodies and throttle cables are disconnected?

[Cogswell]

Interesting dilemma. You can purchase a pressure tester that fits where the rad cap seats. The hand pump attached allows pressurization and there's a dial to watch for leakdown. You might be able to borrow one at Autozone - they have a program for tool rental. If you pressurize it without being full on coolant, it should give you at least a good idea on whether the hoses will hold coolant under pressure.

I'm not sure there is a way to get the cooling system bled without running the engine. Even engines with bleed valves ultimately need to have the coolant circulate to get all the air out. When you do that be sure the bike's on the side stand - that makes the rad cap the highest point in the system and will allow all the air to rise up and out.

[Corey]

I forgot to state that I have a Mityvac Motorcycle Coolant Pressure Tester. I used it to determine that I had a coolant leak.

I figured if I pressure tested without full lines that I wouldn't get an accurate result because the coolant wouldn't necessarily be where I needed it to be, in the lines near the hose clamps, where the leaks would be located.

[Corey]

Here is a photo of the thermostat and one of the water joints. Silly question but, do you think the hose clamps look OK? I re-used the ones that were on the bike. They seem to be in great condition. Interestingly enough, they do seem to have a slight memory of their position on the old hoses. So, I matched the orientation of the original clamps. For some reason two of them are oriented down, which makes them impossible to tighten without completely removing the thermostat.

Also, notice the straight edge in the second photo (indicated by the arrow). Is this a stop point for the hose? If so, I am not sure that I reached them. It was a bear to get it as far as it is in the photo. I wasn't sure it was a stop point because the axis looks off (indicated by the red lines). If it is a stop point and I didn't reach it, will this be a problem?

Now I just have to figure out a way to pressure test the system.

[gmtech94]

Just pump it up to about 10 psi ,that will bleed any air out past the thermostat . Check for being full and then pump it up to 16 psi and check for leaks ,no need to run it and get it warm .

[Rice]

What stops you from attaching the pressure tester to the radiator and doing the test normally?

P.S.

IMHO, you are overthinking this.

If the hoses are new and you have cleaned the fittings and did not overtighten the clamps, there is no reason what so ever for them to leak.

[Mohawk]

Here is a photo of the thermostat and one of the water joints. Silly question but, do you think the hose clamps look OK? I re-used the ones that were on the bike. They seem to be in great condition. Interestingly enough, they do seem to have a slight memory of their position on the old hoses. So, I matched the orientation of the original clamps. For some reason two of them are oriented down, which makes them impossible to tighten without completely removing the thermostat.

Also, notice the straight edge in the second photo (indicated by the arrow). Is this a stop point for the hose? If so, I am not sure that I reached them. It was a bear to get it as far as it is in the photo. I wasn't sure it was a stop point because the axis looks off (indicated by the red lines). If it is a stop point and I didn't reach it, will this be a problem?

Now I just have to figure out a way to pressure test the system.

Turn those clamps over. They were done that way in the factory as its easier & they tighten them with a torque driver, so never need to re-tighten them. If you ever need to snug them down you can't whilst they are upside down. Yes that's a stop, but the hose doesn't need to reach it, so long as there is sufficient for the clamp to grip past the anti-slip lip.

The most important thing to do is make sure all the alloy stubs that the hoses connect to are cleaned up properly before adding new hoses, a little oil helps them slip on & tighten down easily. Use a spare piece of tube between the TB heater points, then fill the system & pressure test, it will take a long time to generate pressure if the system only has air in it !

Have fun :)

[Corey]

I am sure I am over thinking this. I tend to do that with everything. I just don't want to have to pull the bike apart again as it is a bit of a pain.

It never occurred to me that I could pressure test without fluid in the system. It makes sense that an air leak would cause the pressure gauge to fall. It just makes it more difficult to find the point of failure I guess.

How does one "overtighten" hose clamps. I pretty much cranked them down super tight without going hulk on them. Hope that is OK.

In regards to the upside down clamps...will loosening an already tight fit cause issues with the clamp or hose when I go to re-tighten them? I am tempted to just leave them because they are already done and I don't want to mess with anything. But then again I would like them facing up too. Why can't I do it right the first time?

I don't understand "use spare piece of tube between the throttle body heater points?"

[Mohawk]

OK with the clamps, the hose is new, it will only set once its been heat cycled a few times ! So change those clamps & stop over thinking everything :)

The throttle Bodies (TB) has a heat pipe from the cooling circuit, on the left side where the hose from the pump comes round the generator to an alloy stub, with a short piece to the rear head alloy stub, on top of that you will find a nipple, there's one on the right side of the TB but i can't recall exactly where it attaches, could be on the thermostat housing. Either way with the TB removed you should have two uncovered nipples.

Just noticed yours is 1998, so whilst no wax unit for the choke, I assume it still have the TB heating circuit, cures icing in the TB's. If you didn't disconnect two 6mm hoses from the cooling system to remove the TB's then I can only assume the 1998 does not have heated TB's.

Hope that helps.

[adeyren]

If you do pressurize with air get some of this stuff. http://uk.gcegroup.com/products/leak-detection-spray

Alternatively washing up liquid mixed with water in a spray bottle will find leaks.

[Cogswell]

You'll know if you've overtightened clamps by either stripping them out or having the clamps cut in to or significantly deform the hose material. They need to be good and snug but not reefed on. It's a fine balance between "not enough" which it seems is what you might be worried about, and too much. Your pressure test with air will tell you they're good. Sounds like you've got 'em in good order.

[Corey]

Thanks for all of the input so far. I'm far from done, but all of the input has been helpful.

I stared at the thermostat (and the inverted hose clamps I put in place) and almost didn't try to correct the issue and just go with it 1). because of the work involved and 2). because I was afraid I wouldn't be able to re-tighten the hose clamps because I nearly stripped the phillips screw head on a couple. But after thinking it through I decided to give it a go. It was a bit exhausting to do the work again, but I managed. I figured if I ever needed to "snug" them up (like Mohawk said) it would be a pain if they were upside down. I also discovered that I could use a 6mm socket to tighten the hose clamps. I was able to get them a little more snug than I was able to do by hand. I feel better about the snugness, but a couple felt a little to close to stripping out.

How do they look to you? OK? Or too tight?

I have replaced all of the hose but the two (attached to the water joints) in the following photo. I would like some advice on these. They are in good condition and are not leaking at any of the hose clamps or water joints. In order to replace them I have to pull the left side radiator as you can see (indicated by the red arrow) one of the water joint bolts is behind the radiator. My question is whether or not I should go through the effort of removing the radiator and replacing the hoses and water joint seals? Should I take the "if it ain't broke don't fix it" mentality. Or is it better to just do it now? Thanks in advance.

[Mohawk]

If you do pressurize with air get some of this stuff. http://uk.gcegroup.com/products/leak-detection-spray

Alternatively washing up liquid mixed with water in a spray bottle will find leaks.

Never use washing up liquid in or on your bike, its a SALT based cleaner. If you want bubbles, then use CAR WASH, its a salt free cleaner !

Those hoses & that whole area of the bike looks great, so I'd leave them alone, I agree ain't broke don't fix it.

Re the radiator, you only have to undo the mounting bolts, no need to remove it, but as the system is empty makes no difference. The lower rad hoses can get corrosion behind them due to facing up & being in the spray zone from the front wheel.

If you do swap those hoses, flip the hose clamp by your Red arrow, so its reachable with the rad in place.

[Corey]

I went ahead and replaced the remaining hoses and seals. I figured I had them so I might as well use them. I replaced all of the hoses and seals and pressure tested the system. No leaks! What a relief. The coolant hoses replacement job is now done! Let's hope it holds at operating temperatures. Thank you for all of the input! It was a tremendous help.

Below is a list of the parts I used to replace ALL of the coolant system hoses and seals for my 5th Gen.

All the hoses are still available except part #19504-MBG-000 (which is the straight hose from the right radiator directly to the left radiator. Instead I purchased the following part which is from a 6th Gen (2002). It has an extra bend in the hose, but worked perfectly fine. $20.69 #22 HOSE, RADIATOR MIDDLE (UPPER) 19504-MCW-D00

There are 5 hoses that hook to the thermostat for the 1998 and 1999 model years. The 2000 or 2001 model year with the Fast Idle Wax Unit will need water pump part #23 as noted below.

Red highlighted parts are the ones that connect to the thermostat for all model years. It is best to do these with the throttle bodies off. All other hoses can be reached with the throttle bodies on. The blue highlighted part connects to the thermostat for 2000 & 2001 model years only.

1998 Radiator Parts Fiche:
http://www.motosport.com/motorcycle/oem-parts/honda/1998/interceptor-_-vfr800fi/radiator

1998 Honda INTERCEPTOR - VFR800FI OEM Radiator Parts
Price Fiche Image NumberDescriptionPart #
$14.21 #20 HOSE, RADIATOR (LOWER) 19501-MBG-000
$6.78 #21 HOSE, L. RADIATOR (LOWER) 19502-MBG-000
$16.13 #22 HOSE, R. RADIATOR (LOWER) 19503-MBG-000
$18.26 #23 HOSE, RADIATOR MIDDLE (UPPER) 19504-MBG-000 NO LONGER AVAILABLE Instead I used #22 (from 2002 model year) $20.69 HOSE, RADIATOR MIDDLE (UPPER) 19504-MCW-D00

$7.52 #24 HOSE, RADIATOR (UPPER) 19505-MBG-000
$25.89 #25 HOSE, R. RADIATOR (UPPER) 19506-MBG-000 - goes from thermostat to neck filler
$17.46 #27 HOSE, RADIATOR BREATHER 19508-MBG-000 - goes thermostat to right radiator
$19.17 #39 BULK HOSE, VACUUM (5.5X3000)OE 95005-55003-20M

Radiator Hoses Total = $127.45


1998 Water Pump Parts Fiche:
http://www.motosport.com/motorcycle/oem-parts/honda/2000/interceptor-_-vfr800fi/water-pump

1998 Honda INTERCEPTOR - VFR800FI OEM Water Pump Parts
Price Fiche Image NumberDescription Part #
$30.90 #2 THERMOSTAT ASSY. 19300-MBG-003
$12.87 #11 HOSE A, WATER 19525-MBG-000
$7.14 #12 HOSE B, WATER 19526-MBG-000
$47.33 #13 HOSE, WATER BYPASS 19527-MBG-000 - goes from thermostat to water pump
$4.67 #14 HOSE, FR. HEAD WATER 19528-MCW-H00 - goes from thermostat to water joint
$4.67 #15 HOSE, RR. HEAD WATER 19529-MCW-H00 - goes from thermostat to water joint
$2.08 #16 O-RING (23X2.4) Need 2 91304-GC8-003
$1.54 #17 O-RING 47 5X2 91311-KE8-000
$2.04 #18 O-RING (21.2X2.4) (ARAI) Need 2 91331-PC9-003
$11.87 #23 HOSE, THERMOBODY 19512-MBG-D00 - goes from thermostat to Fast Wax Idle Unit (throttle body) Model Year 2000 & 2001 only

Water Pump Hoses Total = $117.36

Tota Cost = $244.81

[TomP]

Thanks or the very helpful parts list, Corkey. My hoses are 15 years old -- I've been thinking I might as well get on it while they're still available.

[JZH]

These are pretty cool, too:

Also sold individually here.

Ciao,

[Mikey]

Corkey, thanks for sharing all this legwork. During my planned Spring maintenance outage coolant hoses was one area I was going to inspect once the plastic is out of the way.

[burnes45]

I am replacing all of the radiator hoses on my 5th Gen. In order to replace the hoses around the thermostat I had to take off the airbox and throttle bodies (which involved disconnecting the throttle cables).

After I change the hoses I would like to pressure test the system to make sure I don't have any leaks. I would like to do this before I put the throttle bodies and airbox back on 1). because it is easier to see if you have any leaks, because nothing is blocking your view and 2). it will save me from having to pull them again if I do have a leak.

My question is this...

How do I pressure test the system with the throttle bodies disconnected?

More specifically, how do I get the system fully filled with coolant without starting the engine and running the water pump?

And how do I "blip the throttle" 3-4 times per the service manual instruction to bleed the air out of the system when the throttle bodies and throttle cables are disconnected?

Bleeding the system without starting the can be done with a "coolant vacuum bleeder". A tool that places a vacuum on coolant system and turning a valve allows coolant to be "Sucked" into system leaves no air pockets and will also let you know if you have a leak because tool will not be able to pull a full vacuum.Has a gauge to show level of vacuum also green red yellow markings. Cost about $60-$120 looks like this.

UVIEW 550500 AirLift II Economy Cooling System Refille

www.amazon.com/550500-AirLift.../B000IHK1VI

Amazon.com, Inc.

[checksix]

Thanks for the detailed listing Corkey. Bookmarked for future reference. My '98 is leaking coolant when the temperature drops below about 45F in the garage, so I figure it's about time to start collecting replacement hoses.