A 355 Coolant Leak Question

I have done a search and couldn't really find an answer to an issue that I am having. I took my F355 out last Sunday and when I got home I noticed that the car was leaking coolant on the passenger side. I let the car sit for a few days and refilled the coolant tank. After I refilled the tank (it only took about 1 - 1 1/2 quarts of coolant), I started the car to check for leaks. It didn't start to leak until the passenger side fan kicked on. It started to bubble out the top of the radiator. Is this a thermostat issue? If this is a thermostat issue, how difficult is it to replace? I would like to get the car running again for the international meet within a few weeks. Can this be replaced through the side vent or do I have to lift the car to get to the thermostat (if indeed that is what it is)? Thanks for all of the great help in the past.

Shawn

 

to access the thermostat, unscrew the 6 nuts that hold on the plastic cover that covers the coolant reservoir and power steering reservoir. Once that is off, you can move the PS reservoir out of the way, or completely drain the fluid, remove the lines, and take the reservoir out completely. we also removed the bonnet for easy access. you should have an easy view of the thermostat from there.

i cant help you with diagnosing your problem though, i just thought id help you get access to the thermostat. since the leak only occurs once the passenger fan turns on, it might be related to the thermostat opening.
sorry i cant be more helpful.

 

If it's bubbling out the top of the radiator itself in front of the wheelwell, and not from a hose, it's probably a separation between the tank and cooling fins, unrepairable. New radiator. Bummer.

 

There are no leaks in the radiator itself. The bubbling is coming from the top cap. I was thinking that the thermostat was not opening since it seems to only be happening when the fan kicks in (when the engine gets hot enough).

Thanks for the idea of getting to the thermostat. I will have to see if it is the thermostat and if so, replace. If not, I guess my driving season will be done for this year since the engine will be coming out, and if I have to replace the radiator, I might as well do it all at once.

Thanks for the help and advice...

Shawn

 

Are you sure it's not overfilled? The cooling system will purge any extra coolant if you over fill it. (not that I recommend this method of figuring out how much should be in there).

The owner's manual is a bit vague about how much coolant should be in the tank. It says to measure from the top, but it's not clear if it's the top of the threads or the top of the tank (which is about a 2cm difference). When I look in mine (1995 355 Spider) when it's cold, it's normally fairly low. Maybe 2-3cm from the bottom. Whenever I try to set it higher than that, it just purges until it gets back to that same level.

 

Mine did that because I overfilled it.

 

The thermostat is not on top of the right radiator.

 

Yes, but when overfilled, it should not leak out the top of the right radiator, as the OP is describing. It should come out the overflow hose on the expansion tank.

 

Could it be just the radiator cap? It is strange that it just started after I added some additional coolant before I went out for a ride. I am hoping that it is not the radiator but if it is, it will need to be replaced. Thanks for all of the ideas.


Shawn

 

I think your problem is the radiator cap. You cannot see the thermostat housing unless the top cover piece is off so it unlikely to be coming from there. I had a similar problem and bought a new cap which solved the problem.

Also, when engine is cold check the level of coolant in the tank. It should not be filled to the top of the tank. If you stcik your finger in you should judt be able to touch it and this is the right level.

Goodluck!

 

The OP says the leak is from the top of the right side radiator...the cap is on the expansion tank on the top of the engine.

I would suspect he either has a leaking hose on the radiator, or a crack in one of the tubes brazed onto the top of the radiator.

I am also wondering if the OP is describing the problem incorrectly, and when he says "... bubbling out of the top of the radiator..." he means the expansion tank?

 

Yes you are right. Unles he took the rear splash wells off it is pretty hard to see the top of the radiator even when looking through the top of the engine.
He must be talking about the cap on the expansion tank.

It would be good if he took a pic of the problem to get a better diagnosis

 

IF, he is describing fluid coming out of he expansion tank, he should not visibly see bubbling, since it should pipe down the small overflow hose. So, either the hose is missing, or the cap may be bad.

I would start with making sure the coolant level is correct, or close to correct. When cold, the level should be no higher than 6cm below the top of the filler neck on the expansion tank. Some cars will spit and puke coolant even at that height, and prefer a couple cm lower. If an equalibrium cannot be found, then a new cap may be in order.

 

I checked the coolant level yesterday and it looked to be fine. I started the car and let it run in my garage until the fans kicked on. Once they kicked on, the coolant started to leak again. This time a lot of the coolant leaked onto my floor. I will order a cap today and replace to see if the at fixes the problem. Since was dark when I started the car, I wasn't able to get any photos. If the leak persists after I replace the cap, I can then move onto the next diagnosis. Thanks everyone for all of your help,

Shawn

 

Shawn, please note my post #13 on setting the proper level. Is the fluid going down the overflow hose or right around the seal on the cap? I do think you may need a new cap, but understand if you overfill the expansion tank, it will continue to spit and puke coolant until it finds its equalibrium.

 

Thanks everyone for the suggestions. As it turns out (and from looking at the diagram of the right radiator), it appears that the top of the radiator has a crack in it. I will have to replace the radiator. Since I will be pulling the engine out this winter (maybe a little sooner now), I will do the radiator along with the belts at the same time. Thanks again to everyone with all of the suggestions. I will take some pics once I start the process.


Shawn