Radiator leak during cold weather start?

[awesomeissquid]

If you using KOYO or CSF. They tend to weep at lower goose neck. I've found, by filling casting groove with FIPG 1282B (any coolant rated FIPG, should do), weep can be mitigated. I let FIPG dry overnight before attaching lower hose.

CSF Rad & new OEM lower hose 1 year after install.
View attachment 2884935
Filed off raised casting keeping shape as round as possible.
View attachment 2884936
Filled in casting groove, using raise blade to form & smooth, then curing overnight.
View attachment 2884937
99.9 % sealed, 1 year later.
View attachment 2884938

To me that sounds like reason enough to just go OEM.

My hoses, tstat, and rad cap are about a year old. Any reason I should replace those when I do the swap? I was thinking of just testing the tstat to confirm it functions properly at least.

 

[2001LC]

That and not having to swap foam over, are main reason I only recommended OEM these days.

 

[skiwpk]

Interesting thread and hope issues are ID'ed. I just had my rad/hoses/clips replaced with OEM a few weeks ago and today noticed leakage from the cap but nowhere else. It's been very cold in Colorado and last week I started it a few times in below zero weather including a morning at -23F! Should I replace the cap? Tstat is <2 years old.

 

[JunkCrzr89]

Interesting thread and hope issues are ID'ed. I just had my rad/hoses/clips replaced with OEM a few weeks ago and today noticed leakage from the cap but nowhere else. It's been very cold in Colorado and last week I started it a few times in below zero weather including a morning at -23F! Should I replace the cap? Tstat is <2 years old.

Was the cap not replaced when the radiator was replaced? Leakage at the cap typically means either the seal under the cap is bad or the hose going from the neck to the reservoir is clogged (or hose inside reservoir).

 

[skiwpk]

Was the cap not replaced when the radiator was replaced? Leakage at the cap typically means either the seal under the cap is bad or the hose going from the neck to the reservoir is clogged (or hose inside reservoir).

I should know more but I ordered the rad, hoses, and clips based on parts diagrams. I didn't think to order the cap also, assuming it's not part of the radiator assembly. I'll start there, hopefully an easy fix. The old rad was leaking in multiple places but I never noticed leakage around the cap.

 

[awesomeissquid]

I should know more but I ordered the rad, hoses, and clips based on parts diagrams. I didn't think to order the cap also, assuming it's not part of the radiator assembly. I'll start there, hopefully an easy fix. The old rad was leaking in multiple places but I never noticed leakage around the cap.

I just ordered the 16400-50360 radiator from the local dealer and should have it in a few days. Looking at the parts diagrams I believe a new radiator cap comes with the radiator assembly.

An update on my end, I pressure tested the system yesterday to 15.6 PSI and did not notice any additional leakage. The gauge pressure did drop 1 PSI over ~30 minutes which I think might have been caused by it being a cheap pressure tester kit. The ambient temp was around 60°F, so if the leak was caused by low temperatures/parts shrinking I might not have seen it anyway. Later today I plan to test the coolant to determine the freeze point since incorrectly mixed coolant could have contributed to a partial freeze up. I also plan to test the rad cap per the FSM which lists a few different test (pump speeds) and specific angles the test rig needs to be held at. I hope this test will help isolate if the gauge pressure drop was in fact due to it being a cheap kit or if there actually is a small leak in my system.

As I mentioned above I have already gone ahead and ordered a replacement OEM radiator ($393 local dealer). I plan to test out the thermostat to confirm functionality and reuse the hoses since all are relatively new (~1yr old). If all the testing of my existing components comes back within the acceptable range, the only cause for the initial leak I can think of would be exactly as @nissanh mentioned with the materials shrinking at different rates allowing a small leak at cold temps. I would hope that this would be extrapolated by the radiator being aged (~4.5 yrs old) and that a new radiator would not have this issue. From what I saw when my leak occurred, none of the other cars leaked coolant when they started. Time will tell if the new radiator fairs better in cold weather, but I would be pretty pissed if the same thing occurred.

 

[oakback]

That and not having to swap foam over, are main reason I only recommended OEM these days.

To add another reason, I went with aftermarket (don't remember the brand, something from O'Reilly's), and one of my mounting holes didn't line up. I think it was for the overflow tank. A ziptie fixed it, but proper alignment would have been nice.

 

[skiwpk]

Confirming that 16400-50360 does include the cap. My cap is new, leak is just below the cap on the neck. Fluid level is very full so must have been a tiny, one time leak.

 

[2001LC]

Confirming that 16400-50360 does include the cap. My cap is new, leak is just below the cap on the neck. Fluid level is very full so must have been a tiny, one time leak.

I've found those caps that come with OEM radiators. Sometimes fit a bit loose. Either I just swap on a new OEM cap, or pinch the caps lips/paws on underside. So to make cap fit tighter.

But also very often, a little bit we see is from spillage during the fill. I like to make sure cap underside dry, wipe top of radiator goose neck, and wash top of rad area after cap on. This way I know if leak.
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To add another reason, I went with aftermarket (don't remember the brand, something from O'Reilly's), and one of my mounting holes didn't line up. I think it was for the overflow tank. A ziptie fixed it, but proper alignment would have been nice.

With respect to aftermarket radiator. My first one I bough online for $90 to my door. Great deal, but damage and fit was a big issue. I struggled with getting shroud side bolt in. Ended up pulling radiator back out. Finding nuts hole partial cover by metal it was weld to back of. What a waste of time. Between that and shipping damage. I never bought online again or have shipped any more. I pickup locally.

OEM is a cleaner and faster install, if one likes all foam. They fitment is perfect both in the engine bay and the OEM hoses. To me they're worth the extra $. But the CSF is what Dealership use on customer replacement around here. Unless service manager writes up as OEM.

 

[2001LC]

To me that sounds like reason enough to just go OEM.

My hoses, tstat, and rad cap are about a year old. Any reason I should replace those when I do the swap? I was thinking of just testing the tstat to confirm it functions properly at least.

I'd not replace, if all new OEM already in. Unless I see some issue(s).

When they come into my shop for new radiator, I do replace all w/OEM. If I've service history showing they've been replaced recently, with OEM parts and have OEM clamps. Than, I do not replace again. I do pull thermostat and check jiggle valve is at top, and look to see if any damage to thermostat. I don't test them any more, as cost of time, is more than just replacing thermostat. I always replace thermostat gasket (O-ring) if it's inlet cap removed and torque cap back down to 13ft-lbf.

BTW. I always start R&R rad service, with washing radiator fins (we 3 rads) and a full drain and blow out of coolant system. If I find block drain(s) clogged with sediment and or sediment in old fluid I've drained out. I do a BG chemical flush..

If any goose neck (inlet cap or outlet from water bypass joint) have pits, I repair. These pits hold/trap coolant and will eat deeper into pit and into hoses.

Note: I read an article once from Alaska, on running 100% coolant. They found it a bad idea, and counter productive. They found it is always best to stick with manufacture recommendation of 50/50 mix. Be it premix or 100% we must mix as close to ~50/50 as we can.