Want to add a quick note-

The only P2M clamp that is failing is on the upper radiator neck due to the bend/corner radius in the neck of the Mishimoto radiator. The welded upper neck continues to bend and doesn’t offer enough flat surface area for the clamp to make an even bite compared to the OEM radiator upper neck (the plastic piece). I’m sure the P2M clamps are fine with OEM radiators when tightened properly, but YMMV still- regardless, they are not constant tension spring clamps so I would avoid them for coolant lines.

 

Inflation affects everything, especially when the Chinese copy proves itself.
I'm bipolar in the car world. I can be loyal to some brands but money leads on the others.

At $45 for the cheapest silicone you still come out $5 under than Autozone replacements.
While you're making the determination of spending $50+ on rubber hoses you think, what's another $40 and if I'm at $100, what's another $100 to cover the entire car in hoses?

I'm a firm believer that the breather hoses are the true cream of the crop for this packet. You can only find these with Chinese intakes only not by themselves. The Breather hoses in silicone are a true necessity to any VQ

Side note:
Only ways for spotting to appear is if the inner liner has failed and is permeating outwards or freak event, leaking hose end leaks onto itself and the exposed fiberglass strands pick this up. The coolant will travel through the middle layer and also bubble as it heats up and tries to exit the hose. Then again for these two something else must be happening inside of the system as well.

 

Are you referring to the plenum PCV breather hoses or intake side PCV breather hoses? I still have a set of Z1 silicone plenum PCV breather hoses as a backup if the OCC lines ever fail or have an issue. I had the intake side chamber delete hoses also, but re-installed them when I installed the Takeda intake. IIRC they are there only for acoustics to help the car sound more bassy/deep. I remember noticing a small (good) difference when I reinstalled them. Side note for anyone curious- Maserati’s acoustic engineers design their air intake boxes using similar Helmholtz resonating chambers to make their V8 sound so good and different from the Ferrari engine it’s derived from (along with some other obvious engine tweaks).

Our logic is very similar- I’m all about paying up for parts, but only where it’s truly deserved, and am not necessarily loyal to some brands but may end up buying more of their products overtime if they just work and don’t fail me. But trying different brands is part of it, and like you said with inflation and name-brand parts manufacturers dropping in quality due to Covid backup etc, times have changed. And production technology has made it much easier for smaller companies to make decent quality products (eBay carbon interior trim I’m eyeing haha). The aftermarket price mark ups have gotten dumb

And for anyone else reading this…yes, oh yes it adds up- have to pay to play, regardless of how much you’re paying and playing!

 

The breathers, I've tried almost every technique possible to make them from a single hose (many different types of material) and everything kinks. Only silicone and clear braided seem to work but it requires a not-so pleasing look vs a stealth looking pre-bent silicone hose. The 90 degree bends that it requires is almost impossible to duplicate. Only other options is to retain those plastic resonator/boxes, add elbows, etc.

The PCV side is easier to find at the parts store already bent.

 

I was going back and forth deciding between the OEM green and Mishi coolant and was at first leaning towards the Mishi Liquid Chill. They key difference is one is propylene-glycol based (Mishi) and the other is ethylene-glycol based (Nissan green and blue). I’m actually much more hesitant to try the Mishi coolant, after reading about viscosity differences between ethylene-glycol and propylene-glycol. Propylene-glycol is more viscous, and as a result is less thermally efficient when compared to ethylene-glycol. Ethylene-glycol has a lower viscosity, which means less friction loss, which leads to better thermal efficiency. I also fear for my water pump running more viscous fluid…so I’ll play it safe with what the Nissan engineers designed the engine & water pump to be used with. Propylene glycol is much less toxic and used in many consumer products, but costs more, which is part of the reason why the Mishimoto coolant costs a good bit more. Going to switch to good ol’ green and run with it, especially since I’ll be flushing it for track days/competitions. No one here using green has reported issues, and it’s only $60 for 2x gallons at my local stealership vs $140 for the Mishi coolant. I’ll take my $80 and save it for the new set of radiator hoses haha - I think I’m safe to run another set of Z1 hoses with the green coolant since so many here and everywhere else have seen no spotting issues with the green coolant. Gates power grip hose clamps on the rad hoses and we should be set, knock on wood.

If I ever have the resources, I’d love to see if a variant of BioGlycol could be developed for use in the automotive industry as a coolant option - “Dynalene BioGlycol (Renewable Glycol) is an inhibited non-toxic corn based glycol heat transfer fluid which offers users performance closer to ethylene glycol with the stability, safety, and non-toxicity of propylene glycol. It offers excellent thermo-physical properties all while protecting your system from corrosion and degradation for years.” (from Dynalene, the manufacturer). Very enticing stuff, haven’t been able to find much info about it for automotive applications though.

Track days will just be water (deionized & demineralized) with some water wetter. Tried and true.

 

Temp fix until I swap the hoses again. Just happy to be able to take it out for a drive and do some more data logging I’ve been needing to get done. Stuck some Tessa tape around the silicone hose/under the clamp area to make sure it doesn’t rip through since it’s just a standard worm gear clamp. Seems to do be doing a great job so far. The P2M clamp was aluminum, so it was super easy to bend it by hand to slide it over the hose and remove it. Embarrassed I didn’t think to just bend the thing to remove it sooner, but either way I still have to replace those hoses and other clamps eventually. No more leaks though for now so I’m a happy camper. I purchased some Gates power grip shrink clamps, but leaning towards using OEM spring clamps when I swap them again. We shall see, I’m a little apprehensive about trying the gates clamps but have heard great things.

 

That radiator neck threw me off

 

Yeah, it has only about a half inch of true straight tubing after the bead roll, not sure why they thought that was a good idea designing/making the neck. You can see it also sticks out a hair further than the OEM neck with how the Z1 hose is a little offset. I might use a Gates power grip clamp there for peace of mind since they supposedly conform well around small bends like that. Past that the radiator has been flawless though.

 

So for some reason there is a ton of conflicting or incorrect info (and a general lack of info) on proper clamps etc to use with silicone hoses and I thought I’d add some info. If you are an engineer and would like to explain this in more detail please feel free to chime in! I am not an engineer, but do my due diligence in research from reputable sources (such as leading manufacturer reports, product data sheets etc). I also wanted to mention that Sebastian Chacoff, owner of and master tuner at SpecialtyZ based in California, personally recommends OEM hoses with OEM constant tension spring band clamps. For silicone hoses, he personally recommends using ABA or Breeze worm clamps.

Both Breeze (made in USA) and ABA (made in Germany) are owned by Norma group, who supplies many of the German car manufacturers with their OEM clamps used in their higher end cars (Porsche, Mercedes, etc.). They make several variations of clamps, some of which I couldn’t even find online such as their new(?) super-seal constant tension worm drive clamps. These clamps use 316 grade stainless steel assemblies and screws, some even featuring 400 series stainless steel screws. I could only find one model available for sale online (without buying bulk), listed below, but if someone can find them, the ABA/Breeze super-seal constant tension worm clamps are the ones to get. Murray makes a very similar dual-bead clamp I listed below, which seems like the best option.

Here’s some basics:
1. Use OEM constant tension spring band clamps for OEM hoses
2. Avoid using T-bolt clamps on coolant lines, as they don’t provide a perfect 360 degree seal (this applies to spring/constant tension T-bolt clamps as well). Some designs/brands are better than others, YMMV.
3. OEM spring band clamps may not provide an adequate seal when used with silicone hoses, YMMV
4. Clamps should have recessed hardware (ie an inner liner/band covering the housing) otherwise they can potentially cut into hoses and/or not provide a uniform seal around the housing
5. Spend up for 316 grade stainless steel clamps, if possible, since they have superior corrosion resistance properties (zinc plated is not as resistant to corrosion)
6. When using worm gear clamps, use constant tension clamps such as the Belleville washer style spring worm clamps, or clamps with a spring insert/spring band liner like the Murray dual bead clamps to provide a true 360 degree seal
7. Flanged band edges will always help prevent the clamp cutting through the hose

And here’s some quality clamp options for silicone radiator hoses (part numbers are listed for use with our radiator hoses):

1. Mishimoto dual bead constant tension clamp (MMCLAMP-WGP-56)
+Securely clamps hoses, couplers, and pipes with an outer diameter from 1.54-in-2.2-in (39mm-56mm)
+High torque worm gear design allows for quick and easy tightening
+Protective inner shield ensures safe, damage free clamping of soft materials
+Innovative double-ridge design provides uniform 360 clamping force
+Double-ridge inner shield design provides concentrated compression force to ensure leak free connections
+304 Stainless Steel construction resists corrosion
+Sold in packs of 10
+Includes Mishimoto Lifetime Warranty
+Readily available and affordable, $20-30 for a 10 pack

2. Murray Dual Bead Shield constant tension clamp (DB28SS305)
+Flanged edges to avoid cutting into hose
+Dual bead design reportedly offers 30% more clamping force using less torque compared to smooth liner clamps
+Provides constant-tension spring action through dual bead insert design
+Murray partnered with Turbosmart to develop their dual-bead constant tension clamps and the Turbosmart branded turbo seal dual-spring constant tension clamps
+Cheaper vs ABA/Breeze, similar build quality using 316 grade stainless steel and optional 400 series screws ($30 shipped for 4x from flexiblepvc.net based in NJ)

3. GReddy dual-bead constant tension worm clamp (22400045)
+30-45mm / No. 24.
+Same design as Murray and Mishimoto dual-bead constant tension worm clamps listed above
+Black coated Stainless-steel hose clamps
+Flanged edges protect soft hoses, such as silicone or rubber, from damages.
+Ideal upgrade for improved looks with the black coating and GReddy laser engraved logo on each clamp.
+8mm Hex / Flathead adjustment head
+Sold individually, around $5 per clamp

4. Breeze (CT200L)
+Constant tension worm clamp w/ Belleville spring washers
+410 SS hex screw, 316 SS clamp
+Suitable for 1 1/4” to 2 1/8” OD hoses
-Flat/smooth inner (no flanged edges), but no reports of cutting into silicone regardless
-Pricey and somewhat hard to find (there are a few sellers on Amazon, $12ish each

5. Gates Power Grip SB shrink clamp (32941)
+Temp resistant from -40F to +302F
+Made from oil resistant thermoplastics
+Uses a standard heat gun to shrink the clamp, contours around bends and out-of-round applications
+No re-tightening or adjustments ever needed after install
+Does not damage hose
+Less to cut your hands on when working in the engine bay, might look cleaner (personal preference)
+Also sold by Pegasus racing (if they trust it, it must work, and most reviews agree)
-Must cut off clamp to remove hose
-Slightly pricey at $5ish per clamp, especially since they can not be reused

 

I've had tbolt style clamps on my silicone rad hoses for almost 3 years now without incident.

If they can hold 30+ psi of boost, then they can hold 14psi of coolant pressure.

 

I’ve also used standard worm gear clamps for years without many issues on other cars, dirtbikes, boats etc that I’ve worked on, and only had one really fail that I can remember. Several friends have used T-bolts on their cars without issues. I wasn’t saying t-bolt clamps won’t work, just stating facts about their general design compared to a spring/constant tension worm gear clamp. Some are better than others, YMMV. And agreed about the pressure rating, no one should ever see coolant lines on our cars go past 20psi, so legitimately no need to worry about a clamp holding 40psi etc in this application.

I listed this info in hopes of preventing others from going through any coolant system headaches- it’s easy to use the right clamps the first time and never have to worry or even think about them again. I searched through different forums, websites, and reviews for info and found people were ditching t-bolt clamps for these clamps, including some WRC Subaru folks who love them (they really dig the Turbosmart dual spring constant tension clamp for turbo/IC piping, I’ve never seen them being used). It might be overkill and my OCD but I like to do things right the first time. Funny it hasn’t worked out that way for me with my own coolant shenanigans. Always hope others can learn from my mistakes instead of having to learn the hard way, here to help.

 

Goldbug you provided lots of good info about the Z1 kit. I just bought the full hose set from them and am doing research on what clamps to use when I came across this thread. This whole thread is exactly what I was hoping to find! I was looking at buying some high quality stainless worm gear clamps but it sounds like constant tension ones or the OEM spring type ones are the best bet.

 

I have the z1 full hose kit and also use the oem style spring clamps on all the hoses. I had to order larger ones because of the thickness of the hose for certain locations

 

Happy to hear this thread is helping others

I’ve been busy training at my new job (Volvo mechanic fwiw) so I haven’t even had time to work on my own car and finally fix my hoses, but so far everything is holding up strong, including the standard worm gear clamp. No spotting on any of the other hoses and what spotting did start has not continued to spread. Maybe they spotted due to the leak, but regardless the other Z1 hoses are solid with the OEM blue pre-mix coolant. No issues, happy I won’t have to mess with the heater hoses again hopefully or switch coolant types. Also grabbed another Z1 coolant bleeder port I threw in, because the latest revision (version 3 it looks like) uses a 5mm hex vs the screw style on the older versions. I have their original bleeder valve also somewhere in storage. Got a few coworkers with Z’s I plan to give them to, if they don’t need or want them I’ll make a FS thread & link it here for free grabs.

Update - Swapped out to my FINAL set of Z1 silicone radiator hoses and still using OEM blue pre-mix, fingers crossed they don’t spot but so far so good. Had the shop use one of the Murray dual-bead constant tension clamps in place of the worm gear clamp on the upper rad neck (no leaks!), but they re-used the P2M clamps in the other 3x spots after I asked them to use the Murray clamps, smh…I had to have our Nissan dealership (same owners/network) do the install at the same time as my new AC compressor; I’ve been way too busy at our Volvo shop to get my car in on a lift to do the ac compressor swap myself sadly, as much as I would have preferred to DIY that install.

Either way, the entire radiator might have to come out shortly so I’ll swap the other 3x rad hose clamps - which I will be doing myself in my shop even if my car has to sit on a lift for a couple days…more on that in my build thread since it gets off-topic. I’ll post some pictures of everything once I swap out those last hose clamps.

 

Updated the clamp list in post #99 to include Mishimoto’s new dual-bead constant tension worm gear clamps. Probably the best option out there for price and availability. Looks like their copy of the Murray/Turbosmart clamps. For our radiator hoses the model is (MMCLAMP-WGP-56).

Post #99