Rads are expensive-87 S4 5 speed alternatives?
06-07-2012, 02:12 AM
#61
Three Wheelin'
Thread Starter
I still haven't bought a rad. Might go with Griffin Radiators. I'm still looking around locally.
Also, one of the reasons for not going with a stock rad is because of the end tank situation. Most of them that are on the original seals won't hold pressure by now. I remember i was going to buy one off of a rennlister here that personally contacted me because he knew i needed one. Well, it looked mint. He pressure tested it and it failed. Why would i get something that might be inferior to something that can be had today for less money?? This to me is a failure of logic... It's not like 928 rads were made of brass and copper FFS.
Oh and to outbackgeorgia,
Aluminum can corrode through a "battery" effect if the pH of the coolant changes when the coolant is not changed frequently enough. There were a bunch of posts about how it works on a thread about stainless steel fasteners in aluminum that i had made, they explain the principles.
It's called "Funny stainless steel fastener companies reply to my question"
Also, one of the reasons for not going with a stock rad is because of the end tank situation. Most of them that are on the original seals won't hold pressure by now. I remember i was going to buy one off of a rennlister here that personally contacted me because he knew i needed one. Well, it looked mint. He pressure tested it and it failed. Why would i get something that might be inferior to something that can be had today for less money?? This to me is a failure of logic... It's not like 928 rads were made of brass and copper FFS.
Oh and to outbackgeorgia,
Aluminum can corrode through a "battery" effect if the pH of the coolant changes when the coolant is not changed frequently enough. There were a bunch of posts about how it works on a thread about stainless steel fasteners in aluminum that i had made, they explain the principles.
It's called "Funny stainless steel fastener companies reply to my question"
06-07-2012, 06:52 AM
#63
Drifting
I still haven't bought a rad. Might go with Griffin Radiators. I'm still looking around locally.
Also, one of the reasons for not going with a stock rad is because of the end tank situation. Most of them that are on the original seals won't hold pressure by now. I remember i was going to buy one off of a rennlister here that personally contacted me because he knew i needed one. Well, it looked mint. He pressure tested it and it failed. Why would i get something that might be inferior to something that can be had today for less money?? This to me is a failure of logic... It's not like 928 rads were made of brass and copper FFS.
Oh and to outbackgeorgia,
Aluminum can corrode through a "battery" effect if the pH of the coolant changes when the coolant is not changed frequently enough. There were a bunch of posts about how it works on a thread about stainless steel fasteners in aluminum that i had made, they explain the principles.
It's called "Funny stainless steel fastener companies reply to my question"
Also, one of the reasons for not going with a stock rad is because of the end tank situation. Most of them that are on the original seals won't hold pressure by now. I remember i was going to buy one off of a rennlister here that personally contacted me because he knew i needed one. Well, it looked mint. He pressure tested it and it failed. Why would i get something that might be inferior to something that can be had today for less money?? This to me is a failure of logic... It's not like 928 rads were made of brass and copper FFS.
Oh and to outbackgeorgia,
Aluminum can corrode through a "battery" effect if the pH of the coolant changes when the coolant is not changed frequently enough. There were a bunch of posts about how it works on a thread about stainless steel fasteners in aluminum that i had made, they explain the principles.
It's called "Funny stainless steel fastener companies reply to my question"
06-07-2012, 02:12 PM
#64
Chronic Tool Dropper
Lifetime Rennlist
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Lifetime Rennlist
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The "end tank failure" situation is hardly a serious problem when you consider how old our cars are now. Replace the tank and use a new o-ring. Clean the radiator while the tanks are off. Clean the junk from the water side of the aux coolers if you have them. Make sure the seating area for the end-tank o-rings isn't corroded. Reassemble.
Meanwhile... All-aluminum radiators are stored-stress bombs waiting to crack. Heating is uneven across the units, since there isn't much thought given to balancing flow beyond what happens naturally due to restriction. It isn't way different from what the original radiator had, but with welded end tanks there is less opportunity for everything to expand and contract correctly. So with all the bending and twisting forces appled, you will get cracks eventually.
We might dream of having AL end tanks with o-ring seals rather than having them welded on. That way the radiator core could move around as needed, and the o-rings would buffer the movement. Best of both worlds. But if the plastic tanks "only" last 25 years or so in service, it's tough to justify the expense of fabricating AL reolacement tanks.
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To the OP's original suggestion about finding another radiator in the aftermarket: Go for it! Look for something that is made for something with similar horsepower, and with additional capacity/headroom to support actually using some of that power on a regular basis. A suggestion in another thread re: cooling fans suggests that the Lincoln Mark VIII has a similar-sized radiator, for instance. Probably doesn't have oil cooler built in though. For the majority of owners, a good ATF cooler is a minimum requirement; 'murrican-car radiators often use a simple loop of steel tubing in the end tank for this, and maybe it's enough. Compare with the mini-radiator that Behr used for ATF in the original radiator. Overkill or essential?
Lots to think about. Meanwhile, the recent 928 International sale on OEM Behr radiators was good enough that I grabbed one and stuck it in inventory. I'm pretty sure I now know what path I'll take when/if my original radiator shows any signs of problems. Meanwhile, fresh coolant every year seems to keep the original working. So Far anyway.
Meanwhile... All-aluminum radiators are stored-stress bombs waiting to crack. Heating is uneven across the units, since there isn't much thought given to balancing flow beyond what happens naturally due to restriction. It isn't way different from what the original radiator had, but with welded end tanks there is less opportunity for everything to expand and contract correctly. So with all the bending and twisting forces appled, you will get cracks eventually.
We might dream of having AL end tanks with o-ring seals rather than having them welded on. That way the radiator core could move around as needed, and the o-rings would buffer the movement. Best of both worlds. But if the plastic tanks "only" last 25 years or so in service, it's tough to justify the expense of fabricating AL reolacement tanks.
-----
To the OP's original suggestion about finding another radiator in the aftermarket: Go for it! Look for something that is made for something with similar horsepower, and with additional capacity/headroom to support actually using some of that power on a regular basis. A suggestion in another thread re: cooling fans suggests that the Lincoln Mark VIII has a similar-sized radiator, for instance. Probably doesn't have oil cooler built in though. For the majority of owners, a good ATF cooler is a minimum requirement; 'murrican-car radiators often use a simple loop of steel tubing in the end tank for this, and maybe it's enough. Compare with the mini-radiator that Behr used for ATF in the original radiator. Overkill or essential?
Lots to think about. Meanwhile, the recent 928 International sale on OEM Behr radiators was good enough that I grabbed one and stuck it in inventory. I'm pretty sure I now know what path I'll take when/if my original radiator shows any signs of problems. Meanwhile, fresh coolant every year seems to keep the original working. So Far anyway.
06-07-2012, 02:31 PM
#65
Three Wheelin'
Thread Starter
You bring up a good point with regards to the expansion and contraction of the end tanks compared to the core. I'll keep looking on eBay for domestic car rads etc. Eventually i'll find something.
06-07-2012, 02:39 PM
#66
Race Car
As someone who is about to get his 21 year old radiator rebuilt I can't really concern myself with a 3rd-party replacement. Unless there is core or side cooler damage on this one, it's good for many, many years.
Car stays pegged at the 2nd notch or below.
Car stays pegged at the 2nd notch or below.
06-07-2012, 02:49 PM
#67
Archive Gatekeeper
Rennlist Member
Rennlist Member
Perhaps I've been lucky as well, but both of the original radiators in my '90 and '93 are original (115 and 104K miles). Back in '07 I bought a spare Behr 'cause I figured I'd need it, it's still sitting on the shelf. I pulled the radiator out of the '93 and installed one of the 78-86 radiators (in order to have an oil cooler I can put in series with the GT oil cooler), but that '93 radiator is fine too. So there are 2 spares on the shelf, probably enough for the next 30 years..... Maybe it's a lower thermal load thing on the 5-speed cars (no ATF cooler on the pass side), or regular coolant maintenance, or good clean living, but I'd be hard pressed to complain about factory 928 radiator performance. (Especially after dealing with the POS Behr plastic radiators used in my E34 BMW- 2 replacement rads in 8 years...)
06-07-2012, 08:56 PM
#68
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I am well versed in various "galvanic corrosion" effects. I was just referring to the term "rust" (used in post 30), usually applied to ferric oxidation. Corrosion I understand. I have been using Dex-Cool without any corrosion issues, but that's another subject/thread.
Leaking tank seals are easily repaired correctly. Corrosion is another issue, not so easy to repair, if at all.
Dave
Leaking tank seals are easily repaired correctly. Corrosion is another issue, not so easy to repair, if at all.
Dave
