So my fiero overheats when driving at highway speeds but not around town, I assumed this was a flow issue however after inspecting my radiator and finding it to be in good enough condition, I jacked up the fiero and found a dent in the return pipe (on the right hand side, as far as I'm aware this is the pipe that sends cool water back into the engine.) It at least looks like a dent to me, its on the right hand side of the car just before the pipe goes up to the engine. I'm assuming that at low RPM the water is moving slower (as I"m not running with a thermostat) where as at highway speeds 3k RPM or higher it overheats out of the overflow bottle and goes on the wind screen and is a pain. I'm thinking that this is the source to my problem as I posted the same issue a little while back where I whined like a little girl.

What I'm thinking of doing is draining the water out of it (also I'm not running any coolant, should I be?) then grinding out the dented section of pipe and then getting radiator hose and some pipe clamps and patching the section that way. I am wondering if that is a good idea as I can't see another way of fixing my problem.

Also another question; I went for a short drive, about 20Kms (or I think that is about 12 miles for the yanks) and when I got back my radiator hose on the left hand side (where the water goes into the radiator) was hot but, the top of the radiator and the radiator cap its self was only just warm. This stumps me as my temp gauge doesn't work so I don't know what the engine is running at temp wise. While I was on that side of the radiator I heard a hissing sound coming out of the left hand side of the radiator, I felt the pipe and it was all crunchy and bad so I need a new pipe, are the eBay ones any good or should I keep looking?

Hating living in Australia and having an American car that is very hard to get parts for.

Coolant tubes are tough to get here too, so its not just because you are in Australia. If the dent is bad enough to impede flow then your workaround of cutting out and using hose to patch the pipe is what most people end up doing.

[This message has been edited by mrfred8 (edited 02-20-2014).]

How far from the end of the tube is this dent? It may be possible to bump it out at a muffler shop.

If you are using only water in your car there is a good chance that the radiator is full of minerals and rust that would make it either not efficient or blocked. The hissing sound may be from water squeezing through a small space inside the core.

[This message has been edited by Gall757 (edited 02-20-2014).]

Is there an efficient way to flush the radiator or am I looking at a new one? If I need a new one is there any cars the share the came radiator as the fiero? when I look at the water in the fiero it is all murky and brown, I just assumed it was from the car sitting around for ages before I bought it. I would love to post a pic on here to show you guys but I haven't got a clue how to work out the Pennocks image poster. Thanks for the help guys.

quote Originally posted by Cruza: Is there an efficient way to flush the radiator or am I looking at a new one? If I need a new one is there any cars the share the came radiator as the fiero? when I look at the water in the fiero it is all murky and brown, I just assumed it was from the car sitting around for ages before I bought it. I would love to post a pic on here to show you guys but I haven't got a clue how to work out the Pennocks image poster. Thanks for the help guys.

Photobucket.com

quote Originally posted by Cruza: Is there an efficient way to flush the radiator or am I looking at a new one? If I need a new one is there any cars the share the came radiator as the fiero? when I look at the water in the fiero it is all murky and brown, I just assumed it was from the car sitting around for ages before I bought it. I would love to post a pic on here to show you guys but I haven't got a clue how to work out the Pennocks image poster. Thanks for the help guys.

Don't know how it is in Australia, but here in the States radiators can be rebuilt without much problem. The shop takes it apart and re-fluxes it back together, and then you are assured that all the tubes work again. The fluid should never look murky and brown. A lot of people think that the stuff in your coolant is just anti-freeze, but it does a lot more than that and it should be in your car to protect the various metal parts.

edit: if you are not running a Mac you should be able to use PIP. just click the box at the bottom of the page and follow the instructions.

[This message has been edited by Gall757 (edited 02-20-2014).]

quote Originally posted by Gall757: Don't know how it is in Australia, but here in the States radiators can be rebuilt without much problem. The shop takes it apart and re-fluxes it back together, and then you are assured that all the tubes work again. The fluid should never look murky and brown. A lot of people think that the stuff in your coolant is just anti-freeze, but it does a lot more than that and it should be in your car to protect the various metal parts.

Doesn't antifreeze also raise the boiling temperature of the coolant? Water not under pressue boils at 212^o F and I think a 50/50 mix not under pressure is supposed to boil around 225^o F if I remember correctly. Under pressure those temps rise a bit but the mix always boils at a higher temperature.

As to the OP's post. If your having boiling problems on the highway it sounds like you are frequently filling the radiator back up. Are you following the correct fill procedure to make sure your not leaving air in the system? Have you checked your radiator caps to make sure they are the correct pressure and that the gaskets in them, the rubber rings, have not gotten hard or cracked? I have a Neon that would occasionally boil in the overflow when I drove the car for longer than "normal" trips. It never boiled over and the coolant was full when I checked, so I didn't start looking for the problem right away. When I finally started looking I found the radiator cap gasket had gotten hard and cracked around the center. This lowered the boiling temperature of the coolant as it was no longer "under 14 PSI of pressure" so when the coolant got hot enough it would boil and the steam would come through the bad gasket on the cap and out the overflow. Basically, the coolant tube "could" be the problem but there are many other things it "could" be also.

Have you tested the flow you may find it is clogged with corrosion and the dent isn't affecting it as much as the build up narrowing the inside pipe diameter.