Protege5 Coolant loss at/near radiator

[katapaltes]

Hey, everyone. I have a leak in my cooling system that has lowered my overflow reservoir from High to Low twice over the course of two 10 - 20 mile trips. The radiator is still full and I've just been filling the overflow back up with a 50/50 mix for the time being. While troubleshooting, I took off the air intake and found coolant all the way around the top of the radiator. (In the pics below, the "teeth" on the front, back, and both sides of the radiator top have coolant on them.)

I thought I'd need to replace the radiator, but I also noticed I have an ill-fitting upper radiator hose. It seems to have backed off from being pushed up snugly to the radiator and there's an obvious gap shown below. The circled spot on the radiator may have even been cleaned by escaping coolant. The witness marks on the radiator hose may be deep enough to interfere with repositioning the clamp - I don't know.

My question is, should I replace the upper radiator hose (and potentially the lower one while I'm at it)? I've already snugged the upper hose to the radiator, but there's still a gap within/near the circle shown in the pic below. I have a worm gear hose clamp that I could add to existing spring hose clamp to cinch down the gap if that would help or just as a troubleshooting step. Both pics below were taken before I snugged up the hose to the radiator, so it looks a tiny bit better now.

 

[LankyKiwi]

I'd say that spring clamp has lost some of it's spring, I'd pull the top hose and replace it with a hose clamp just in case, also inspect the inside of the hose and the neck of the radiator for any damage or crud that could be causing the hose to sit funny. If there's any damage to the hose, replace it. They're cheap enough in any case. The hose should sit right up against the flange on the neck and the clamp should sit around 5mm / 1/4" back from there

My car is doing nearly the same thing with coolant on top of the fins, gonna go check the hose soon

 

[katapaltes]

I replaced the upper radiator hose today. It would have been a great time to replace the coolant, but I'm not sure that replacing the hose will fix the leak. Is it normal for the new hose below to NOT have been cut at a 90-degree angle on the end? That seemed pretty bad, so I used my very sharp MAC kitchen knife to cut it (mostly) straight. I thought Gates-brand hoses would be good, but maybe not.

It looked like the plastic radiator neck had lost a little of its top layer as you can see below. Is that a big deal? I cleaned up the necks on both the radiator and the engine with a green kitchen scouring pad.

I used a bungee cord to secure the empty, yellow Prestone container to capture the escaping coolant. My neighbor works on cars and I told him "it's my auxiliary coolant tank." He looked at me like I was nuts until I told him I was kidding. Pic below is of old hose. I transferred the collar/sleeve thing in the middle to the new hose. Not sure what it's for as I don't see anything that would rub on the hose except maybe the fan shroud.

 

[LankyKiwi]

That hose definitely should have been cut at 90, someone's been at it with some hose cutters
Squaring up the cut was the best thing to do here
Radiator neck should be fine, it's just discoloured from the coolant that's been escaping

From memory the sleeve is for rub protection on the air intake

Hopefully a new, freshly seated hose solves the issue!

 

[katapaltes]

From memory the sleeve is for rub protection on the air intake

Ha... I didn't even think about the hose's rubbing against the air intake as I hadn't yet reinstalled the intake in the pic above. I just went out and checked and yeah, the two are in contact/close proximity.

So far, no signs of leaking, only the system's pulling some coolant from the overflow reservoir which is expected. I've only driven it about 20 miles and I'll drive some more today in our ongoing 100+ degree heat. I did reuse the hose clamps as they looked to be in good shape and were still firm. I've got the old hose, water, and a tool box in the hatch in case I get stranded.

I'm pretty sure there's some loss of material (plastic) from the neck of the radiator and it's visible in the pic above. I don't think it's enough to cause problems, though.

 

[katapaltes]

Hi everyone, an update and a question: I'm still experiencing coolant loss with no signs of leaks coming from the hose replaced above. The leaked fluid is visible all around the top of the radiator as shown above. Does this definitely point to a leaky radiator? Do these radiators just leak at their top (where metal meets plastic) when they get old? I'm ready to replace it, but would like to ask you guys if the problem could be anything else before I do that.

Do I need to worry about getting a specific radiator for my manual transmission vehicle which omits the ports needed for automatic transmission cooling lines, or will the seller typically provide plugs for those ports for compatibility with a manual transmission? Every radiator on Rock Auto seems to have ports for automatic transmissions, and there's no mention or pictures of any plugs.

I might want to get a Denso one as I like that brand. I found a YouTube video where Denso 221-3506 is suggested. Amazon says that part does not fit a 2003 Protege5 (while eBay says it does fit) so I am confused. Time for further research.

Mazda Protege Radiator Replacement (2002)

2002 Mazda Protege LX replacement. Radiator lived for 20 years and 195,000 miles. Nice job, Denso! Unfortunately, it died like most OEM radiators do - at ...

www.youtube.com

 

[katapaltes]

My car is doing nearly the same thing with coolant on top of the fins, gonna go check the hose soon

I let the car idle with the air intake off for five minutes and that was enough to clearly see that the radiator itself was leaking near its top, and at a point far from the filler neck/hose. Previously, I would drive home, remove the air intake, and see fluid spread all across the top of the radiator, and I couldn't tell where the fluid was coming from.

I've ordered the Denso 221-3506 from Amazon as I like the brand and the price is right ($100 US, supposedly on sale). Again, Amazon says it doesn't fit, but I've seen multiple references that it does fit.

Oh, and I finally came to understand that I don't have to plug those automatic transmission lines. With a manual transmission, I can just leave them open or cover them with soft rubber plugs if Denso happens to provide them.

Side notes: You can see the tell-tale signs of a coolant leak in some of the pictures above. When the coolant dries, it leaves little white flakes on surfaces. And the last time I opened the hood, I could smell the coolant.

 

[katapaltes]

Got the new radiator from Amazon installed today. Part is a Denso 221-3506. It's spec'd for an automatic transmission, but I understand that it works in my manual transmission-equipped vehicle. Everything fits great except the radiator cap... Wait, what? I had to go to O'Reilly and buy a radiator cap for an automatic transmission and that fit just fine.

I understand that radiators can be different between a manual transmission and automatic transmission-equipped vehicles, but why on Earth would that difference extend to the radiator cap? The first Murray cap below (7037, for a manual) looked exactly like my original cap and didn't fit the new radiator in the exact same manner as my original. The second cap (7516, for an automatic) did fit.