DAP Posted March 11, 2017 Share Posted March 11, 2017 I have been trying to replace my radiator cap for about a month now. I have a 2005 Subaru Legacy GT Ltd. (Bought in 2004). Subaru tells me the part number is 45137AE00B (this is the one that goes on the external reservoir (not the overflow tank). parts.subaru.com tells me the part number is 45137AE00B, I bought this, and it does not fit. The old main seal is 30.5mm diameter, the new seal is 27.9mm in diameter. The new seal slips past the seat and the spring does not get compressed when the cap is installed. I also tried to buy a 3rd party part from O'Reilly Auto parts. They sold me a Murray 7516. This also does not fit. Its even worse because the rubber seals are thinner. All other online retailers I've tried tell me to buy the same Murray 7516 part. SubaruParts.com and SubaruOnlineParts.com both have a broken parts seach. None of the diagrams they show even show the tank that this radiator cap is on. When I finally found the part number elsewhere, they showed this cap on the radiator, but that one is part number 45137FE002 (This part fits properly there, I bought this one too) What is the correct part number? Link to comment Share on other sites More sharing options...
Shadow_419 Posted March 11, 2017 Share Posted March 11, 2017 45137FE002 Think this what you're looking for. Link to comment Share on other sites More sharing options...
Infosecdad Posted March 11, 2017 Share Posted March 11, 2017 Try parts.subaru.com http://parts.subaru.com/p/Subaru_2005_Legacy25L-TURBO-5MT-4WDGT-Limited-Sedan/CAP-ASSEMBLY-RADIATOR/49251983/45137FE002.html Shadow is right, 45137FE002 is the cap for the radiator. Link to comment Share on other sites More sharing options...
Sgt.Gator Posted March 11, 2017 Share Posted March 11, 2017 Note the Expansion Tank (up by the turbo) uses a different cap from the Radiator! Because they look alike and fit alike it is common to reverse them or replace a defective one with the wrong cap. There is a difference! If you get them wrong it can lead to weird cooling issues that will drive you insane trying to track down what the problem is. If you have cooling issues the first thing to do is check you have the right cap in the right place. Be wary of aftermarket performance radiator caps with a higher bypass. For example Mishimoto states clearly that you do not use the 1.3 bar cap supplied with their performance radiator for the radiator! Here's what they say: "Included 1.3 bar radiator cap raises the boiling point of engine coolant to provide a safer and more efficient system" But then the fine print! Caution The provided Mishimoto radiator cap should replace the stock cap located on the expansion tank. The stock cap attached to the radiator should be installed on the Mishimoto Performance Aluminum Radiator. The Mishimoto radiator cap is a two way valve, while the stock radiator cap is a single valve. Due to the difference in construction, the Mishimoto cap cannot be used on the radiator. If the Mishimoto cap is fit on the radiator, overheating may occur. And to confuse you they show the supplied high pressure cap ON the radiator! https://www.mishimoto.com/subaru-wrx-impreza-sti-performance-aluminum-radiator-01.html This is what the Expansion Tank OEM Cap looks like. It has "Ears" and marked 108 KPA. Part Number: 45137AE00B. You can also use the WRX/STI cap: 45137AE003 http://parts.subaru.com/images/parts/subaru/productimages/fullsize/45137AE003%201.jpg This is the Radiator Cap. No "Ears" and marked 137 KPA: Part Number 45137FE002 http://parts.subaru.com/images/uploads/(101)%20parts.subaru.com/fullsize/a_20150812_1011320756.png You can remember them because Subaru wants you to fill-flush-service thru the expansion tank so that cap has Ears. They don't want you to use the Radiator cap so it has no ears. Nothing like a race track to find the weak points in man and machine. "Good Judgement comes from Experience. Experience comes from Bad Judgement" Link to comment Share on other sites More sharing options...
DAP Posted March 11, 2017 Author Share Posted March 11, 2017 Try parts.subaru.com http://parts.subaru.com/p/Subaru_2005_Legacy25L-TURBO-5MT-4WDGT-Limited-Sedan/CAP-ASSEMBLY-RADIATOR/49251983/45137FE002.html Shadow is right, 45137FE002 is the cap for the radiator. This is the part that goes on the radiator. I bought this and it fits on the radiator. The problem I am having is with the other one, the one that goes on the external tank, the one with ears. The original and the replacement look the same, except for the disk of rubber on the original is bigger than on the replacement. The original needs to be pressed down to compress the spring to install, the replacement only needs to be placed on the tank and rotated to tighten. It is as if the spring loaded seal is not engaging at all. Link to comment Share on other sites More sharing options...
Infosecdad Posted March 11, 2017 Share Posted March 11, 2017 This is the part that goes on the radiator. I bought this and it fits on the radiator. The problem I am having is with the other one, the one that goes on the external tank, the one with ears. The original and the replacement look the same, except for the disk of rubber on the original is bigger than on the replacement. The original needs to be pressed down to compress the spring to install, the replacement only needs to be placed on the tank and rotated to tighten. It is as if the spring loaded seal is not engaging at all. Apologies, your first sentence was "I have been trying to replace my radiator cap for about a month now." and that was the radiator cap. Looking up the part number for the overflow matches what you were told (45137AE00B). I have an '05 as well (build date of 02/05), the inner metal part of my expansion tank cap is 29.05mm and it hasn't been replaced as far as I know. The rubber seal on the end is slightly bigger than the inner metal part and I think that is expanding over time. If the dimensions of your inner metal part is the same as mine, I'm wondering if the difference is the rubber seal part just expanding with age. Link to comment Share on other sites More sharing options...
DAP Posted March 11, 2017 Author Share Posted March 11, 2017 I have added pictures of the radiator caps I bought vs the original. 1st picture is murray on right, second is replacement subuaru on the right. Link to comment Share on other sites More sharing options...
Infosecdad Posted March 11, 2017 Share Posted March 11, 2017 Is the diameter of the metal part behind the rubber the same on the replacement caps as your original one? Link to comment Share on other sites More sharing options...
utc_pyro Posted March 11, 2017 Share Posted March 11, 2017 Can confirm 45137AE00B fits, I replaced both my caps a few months ago with OEM due to the odd cooling issues Sgt.Gator was talking about. When you say is doesn't compress, are you saying that it slips entirely through the lower hole into the tank or just isn't as tight? Mine wasn't hard to put in, and it's holding pressure just fine. Link to comment Share on other sites More sharing options...
MilesA Posted March 11, 2017 Share Posted March 11, 2017 Can someone describe the symptoms of the weird cooling system issues you would see if the caps were not correctly installed? Sgt.Gator? Link to comment Share on other sites More sharing options...
utc_pyro Posted March 11, 2017 Share Posted March 11, 2017 In my case, loss of coolant. Air kept getting into the system and I couldn't find a leak. Then read the part of the FSM covering radiator caps, and realized what was going on. Link to comment Share on other sites More sharing options...
Sgt.Gator Posted March 12, 2017 Share Posted March 12, 2017 Miles, besides what UTC-Pyro said, you can get overheating. Some guys have chased their tails replacing thermostats, water pumps, radiator flushes, thought they had air pockets trapped in the lines, all because of the wrong caps. Dap you have me curious now. Sunday I'll compare my Mishimoto cap, Spec B cap, and STI cap, then get back to you. Nothing like a race track to find the weak points in man and machine. "Good Judgement comes from Experience. Experience comes from Bad Judgement" Link to comment Share on other sites More sharing options...
DAP Posted March 12, 2017 Author Share Posted March 12, 2017 Is the diameter of the metal part behind the rubber the same on the replacement caps as your original one? I think so. I'll measure it when the engine cools. Update: Yes they are the same diameter. Link to comment Share on other sites More sharing options...
DAP Posted March 12, 2017 Author Share Posted March 12, 2017 Can confirm 45137AE00B fits, I replaced both my caps a few months ago with OEM due to the odd cooling issues Sgt.Gator was talking about. When you say is doesn't compress, are you saying that it slips entirely through the lower hole into the tank or just isn't as tight? Mine wasn't hard to put in, and it's holding pressure just fine. The seat seems conical, so a smaller seal would fit down lower. I think it may seal, but it certainly won't hold 15 PSI. I drove the car with the new cap installed, my radiator fluid was still boiling. If at least sucks the overflow fluid back into the radiator, it will be an improvement over the state of the original cap. Part of the problem is that I was trying to determine where the leak is in the radiator system. Trying to narrow down the location by replacing the cheapest part 1st, but with the part not matching the original, and the fluid still boiling, I have not narrowed down the problem at all. I'm mostly suffering an air leak, air being sucked into the radiator as it cools rather than radiator fluid. If there is a leak somewhere other than the caps, it is very small and I have not seen evidence of it yet. Link to comment Share on other sites More sharing options...
utc_pyro Posted March 12, 2017 Share Posted March 12, 2017 The seat seems conical, so a smaller seal would fit down lower. Odd, is your coolant tank aftermarket? Mine has a wide flat seating surface that the rubber seats with. The "conical" portion of it is just the radiused edges of the hole going from the neck into the tank. But the unfindable air leak was my issue. Was completely resolved by cleaning the seats and switching back to oem caps (had mishimoto on radiator that came with it). Link to comment Share on other sites More sharing options...
DAP Posted March 12, 2017 Author Share Posted March 12, 2017 Odd, is your coolant tank aftermarket? Mine has a wide flat seating surface that the rubber seats with. The "conical" portion of it is just the radiused edges of the hole going from the neck into the tank. But the unfindable air leak was my issue. Was completely resolved by cleaning the seats and switching back to oem caps (had mishimoto on radiator that came with it). The tank is original to the car. You are right, the seat is flat, I was fooled by the radiator fluid sitting on the seat. I measured the diameter of the hole, it is 20 mm, so the difference in outside diameter of the rubber gasket is irrelevant. Looking very closely at the two, the only real difference that would matter that I found was the thickness of the rubber seal. The original is 1.68mm, the new one is 1.48mm. This matches the difference in hight between the two seals and would probably account for the difference in feel when I mount the radiator cap. The Murray cap was down right loose when I put it on which made me very suspicious of everything else I tried. So it looks like the radiator cap is correct for the car, and I have a small leak elsewhere in the system. Link to comment Share on other sites More sharing options...
Max Capacity Posted March 14, 2017 Share Posted March 14, 2017 FWIW, I went to the local dealer and bought both caps for around $20. I did that a few years back when the car was 10 years old...it just made sense for the age of them. The seals were less then perfect. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Sgt.Gator Posted March 15, 2017 Share Posted March 15, 2017 So it looks like the radiator cap is correct for the car, and I have a small leak elsewhere in the system. It's been mentioned here before and on other Subaru forums, several of us use the UView 550000 Airlift Cooling System Leak Checker and Airlock Purge Tool Kit, works great. It creates a vacuum then you fill the system. You may be able to find your leak using it. I've never used it for leaks, but it sure makes filling the system easy and no airlocks. Nothing like a race track to find the weak points in man and machine. "Good Judgement comes from Experience. Experience comes from Bad Judgement" Link to comment Share on other sites More sharing options...
DAP Posted August 6, 2017 Author Share Posted August 6, 2017 Update: I never could find the leak, I continued to hear gurgling of radiator fluid at stoplights. A couple of days ago, I heard a couple of squeals while driving on the freeway. When I got off, I saw steam rising from under the hood. The aluminum to plastic seal gave way on the radiator. i got the radiator replaced, and the gurgling has gone away. I had checked the seams very carefully before and never saw any evidence of the leak. After the squeal, I saw a spray of radiator fluid aimed at the engine. My guess is that the leak was like a squirt gun, shooting the radiator fluid somewhere where I could not see it, and only when the pressure in the radiator was high. Link to comment Share on other sites More sharing options...
Max Capacity Posted August 6, 2017 Share Posted August 6, 2017 Got to love those plastic radiator tanks...I guess the bean counters thought they were a good idea...may be they figured that some day they would need to be replaced after the warranty ran out and they could make more money selling replacements. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
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