Replace Radiator Cap vs Replace Radiator

[DavidProehl]

I get a slow drip in the front of the car for a day or two after driving it. Originally I was thinking this was a small crack in the original radiator, I've been half expecting it to die on me one of these days. I was all ready to put in a new radiator and low power fans, but after closer inspection it appears to be the radiator cap (pictured below). So I suppose the easy fix is to spend $5 on a new DMCH radiator cap, and I'll likely do that either way, but since I was all geared up to replace it I'm tempted to do so now as a preventative measure.

Does anyone out there trust their OEM radiator? Would I be a fool to leave it in (assuming a new cap fixes my leak)? This thread (http://dmctalk.org/showthread.php?2908-radiator-advice) seems to suggest I should replace for peace of mind if I'm ready/able to do so.


12602

[stevedmc]

Original DMC radiators have plastic tanks. In my opinion its best to avoid plastic in a cooling system whenever possible. If it were my car I would call up DMCMW for a new radiator even if your tank seems fine.

On another note, you don't need to order a radiator cap. You can get 16lb radiator caps at Autozone for about $6. My radiator cap went out at DCS and I had a spare Autozone part sitting in my car. I put it on the car, filled with coolant which I keep with me also, and drove the rest of the weekend and the 10 hour drive back home with zero problems.


Edit: I was talking about the "radiator" cap that goes on the coolant tank. I just looked at your picture. I don't remember if my original radiator had a cap on it or not. Check and see if your radiator has plastic tanks. If it does, I would replace it regardless.

[stevedmc]

On another note, how old are your coolant hoses?

[DavidProehl]

Original DMC radiators have plastic tanks. In my opinion its best to avoid plastic in a cooling system whenever possible. If it were my car I would call up DMCMW for a new radiator even if your tank seems fine.

On another note, you don't need to order a radiator cap. You can get 16lb radiator caps at Autozone for about $6. My radiator cap went out at DCS and I had a spare Autozone part sitting in my car. I put it on the car, filled with coolant which I keep with me also, and drove the rest of the weekend and the 10 hour drive back home with zero problems.


Edit: I was talking about the "radiator" cap that goes on the coolant tank. I just looked at your picture. I don't remember if my original radiator had a cap on it or not. Check and see if your radiator has plastic tanks. If it does, I would replace it regardless.

Yes, I have the plastic tanks on the sides. I figured it would probably be in my best interest to just replace them. Thanks.


On another note, how old are your coolant hoses?

I put new coolant hoses on last fall. They should be good.

[Chris4099]

I'm pretty sure on the original radiators, that cap is not removable like a regular "radiator cap". Mine did that too and I just replaced the whole thing. No point in fixing something that will still leak elsewhere soon enough.

[stevedmc]

Yes, I have the plastic tanks on the sides. I figured it would probably be in my best interest to just replace them. Thanks.



I put new coolant hoses on last fall. They should be good.

I would definately replace that radiator if it has plastic tanks then. The new radiators don't have caps on them if I remember correctly.

You might want to check your hose connections if they are new. Unless coolant is dripping from the radiator to the hoses, it appears you might have some loose clamps as well. You can rent a pressure tester from Autozone for free that will make it easy to check for leaks.

[DMCMW Dave]

I'm pretty sure on the original radiators, that cap is not removable like a regular "radiator cap". Mine did that too and I just replaced the whole thing. No point in fixing something that will still leak elsewhere soon enough.

That tiny cap on the radiator does come off. It is available. If you remove and replace it, or tighten it, one of four things will happen. We've seen all four personally:

A - It will stop leaking;

B - It will stay the same;

C - It will get worse;

D - You will snap the neck off the radiator.

About equal chances actually.

[David T]

I tried to fix a leak there for someone and eventually we pulled the rad. Turned out the neck had a crack in it. If you still have the OEM rad with the plastic tanks, get it out and replace it. Don't waste any time on it, it is WAY past due for replacement.
David Teitelbaum

[jawn101]

Wait, THAT'S what the original radiator looks like? I actually had no idea.

I guess it's confirmed that I don't have an OEM one then, mine looks nothing like that. I don't think it even HAS a cap. :)

[82DMC12]

Wait, THAT'S what the original radiator looks like? I actually had no idea.

I guess it's confirmed that I don't have an OEM one then, mine looks nothing like that. I don't think it even HAS a cap. :)

New radiators don't have caps. All metal and sealed.

[82DMC12]

David, looks like the right most hose clamp is leaking?

[jawn101]

My radiator has been bothering me forever. It works fine and doesn't leak, but I had no idea if it was new. The part isn't available on Houston's site so I don't even know what the original one looks like. I also, for some reason and much to my own embarrassment, can NOT tell if the side tanks are plastic or metal. If I tap on them with a screwdriver or a ring, they sound sorta metal-ish? They are not magnetic. They are black, so the paint/coating may be what's confusing me - I can't tell. But it sure doesn't look like David's. The other D I see frequently definitely has an aftermarket one but I never thought to look at David's in all the times I've seen his car.

[Tillsy]

I also, for some reason and much to my own embarrassment, can NOT tell if the side tanks are plastic or metal. If I tap on them with a screwdriver or a ring, they sound sorta metal-ish? They are not magnetic.

The new radiators are aluminium - thus not magnetic.

[Bitsyncmaster]

The plastic tanks will have tabs folded over the edge to hold the tanks on. I would think metal tanks would be soldered (brass) or welded (aluminum).

[DavidProehl]

Thanks again for all the feedback! I'll confirm my hose clamps are properly secured, I see what is being said about the leak there, I had figured it was fluid running down from the cap. I'll go ahead and replace the radiator. Another call to DMCMW next week!

[Chris4099]

Another way to tell if it's metal is almost all metal radiators I've seen have a drain petcock on them. Plastic ones you have to disconnect the lower hose to drain them.

[jawn101]

Another way to tell if it's metal is almost all metal radiators I've seen have a drain petcock on them. Plastic ones you have to disconnect the lower hose to drain them.

Aha. I am 99% sure I have a drain petcock. That side of the car is crammed up against my shelves in the garage so I can't check but I really think I remember seeing one on the passenger side.

[DavidProehl]

To close the loop on this thread:

I finished the job today of installing a new radiator I bought from DMC Midwest. Went in without a hitch. The job was much easier than I expected and the new radiator fit just as well as the original. Also replaced my OEM fans with Toby's low power fans since I had it all out. Then, just to firm up the cooling system, finally replaced my OEM header bottle with the stainless steel version. My cooling system is now leak free for the first time since I bought the car! What a great feeling!

Some pictures of the job:

Old radiator with new fans about to be installed in shroud:
14928

New fans on new radiator:
14929

New header bottle installed with old bottle above:
14930

[jawn101]

To close the loop on this thread:

I finished the job today of installing a new radiator I bought from DMC Midwest. Went in without a hitch. The job was much easier than I expected and the new radiator fit just as well as the original. Also replaced my OEM fans with Toby's low power fans since I had it all out. Then, just to firm up the cooling system, finally replaced my OEM header bottle with the stainless steel version. My cooling system is now leak free for the first time since I bought the car! What a great feeling!

Some pictures of the job:

Old radiator with new fans about to be installed in shroud:
14928

New fans on new radiator:
14929

New header bottle installed with old bottle above:
14930

Looks great David! Nice job. Have you tried it on the road to see if it seems to stay any cooler?

[DavidProehl]

Looks great David! Nice job. Have you tried it on the road to see if it seems to stay any cooler?

Not yet. Just fired it up to bleed the system of air and test the fans.

I have never had problems with the engine running too hot, but I always watch it closely. The main heat problem I've had has been with the fuel pump choking, but I seemed to have fixed that with the spring in the pickup line trick a year and a half ago.

[GS450-Junkie]

Is it possible to replace the fans without removing the radiator?

[Bitsyncmaster]

Is it possible to replace the fans without removing the radiator?

Yes.

[DMCMW Dave]

Is it possible to replace the fans without removing the radiator?


Yes.

Depending on the level of rust.

[jawn101]

Yes but not all that easy...