rickjaffe

looks like I've got a radiator leak. had the radiator drained about two and half weeks ago (not crankcase); added about two gallons.
had to add half gallon about about a week ago;

yesterday took the car on the highway for about 30 miles total; some hard shifting driving/ no coolant light, but I did have quiet a puddle of fluid underneath. and I had to add almost another two quarts of water.

any problem using either a basic "stop leak" radiator product, or dye which will reveal where the leak is under a black light?

I guess the big concern is whether the leak is from the water pump. I think it was changed within the last 4 years and 10k miles.

ZEUS+

It would be best to pressure test system to isolate leak(s). Stop leak can be helpful in an emergency situation. It is wiser to repair than bandaid.

rickjaffe

thanks,

off topic: noticed you have rmb and x pipes on an 88. do you find both too loud?

got rmb, and I'm finding it alittle to quiet for a sports car. not much different from my old lexus sc400.

also with both, do you detect any performance difference with the chip?

ZEUS+

I like the way it sounds, only loud when called upon. All mods combined work well.

chaadster

RMB'd 928 sounds not much different than SC400? Are you sure you've got an RMB?

SharkSkin

Best additive to check for leaks -- pressurized air. Go to the hardware store, get a short length of 5/16" hose, two 5/16" hose barbs, two tee fittings, a gauge and a schrader valve. Connect all of this to the small top hose on the radiator(be careful you don't break the plastic nipple). Fill the system back up, and pressurize to no more than 15psi. You should be able to see where the water is leaking.

Alternatively, you could buy/rent a pressure tester that attaches in place of the radiator cap, but the method I described will also test the cap. The cap should maintain ~15 psi but not much more -- it should relieve pressure above that point.

rickjaffe

pretty damm sure; the rear muffler is in an outside closet. Bought the rmb from a site sponsor.

with due respect, not sure some of you guys appreciate what a sports car should sound like. was on the highway with the windows down and sunroof open and stereo on, and I coudn't even hear the engine.
really not much different from the sc400, same concept I guess, a GT. but I expected different from a porsche. What I'll give it, it is quick, very quick. seems faster than a 6 second 0-60. (have an auto)

seems to me in a sports car the thing you should hear most is the engine.
rmb has a low growl. kind of like what my dog does when another dog passes by, before he starts barking.

have an old 4 carb mid engine ferrari; never use the radio, why do mozart or the beatles when you can have Enzo conducting. the small block vette with an edelbrock is scary loud when I punch it. hell even the bentley with a chevy 400, supercharged sounds more like a sports car than the 928. You guys are mightly refined. I want more raw and visceral.

SharkSkin

I keep hearing "your car is loud" from different people, but from inside it doesn't seem to be. Try rolling down your window & find a parking garage or tunnel.

WallyP

Locate the leak before trying anything else.

Some places to check:
Look under the intake with a flashlight - the water cross-over, thermostat, etc., can leak in the Vee.
Use a strong flashlight to look at the passenger side of the radiator near the upper radiator hose, even though this leak sounds bigger than the usual plastic tank crack.
Pull the air cleaner box and check the hoses and connections on the back of the engine.

rickjaffe

I'll try that, though I might throw in some dye to help with the process.

next question. are radiator hoses anything special? can I just go to my local auto shop, and get standard radiator hoses and cut as needed? that even worked with a ferrari, so I'm hoping I can do the same thing with the 928.

auzivision

What is this “usual” plastic tank crack...leak?

My radiator is weeping and it appears to be on the passenger side metal/plastic junction just below the upper hose. It just drips a tiny amount.

Is this repairable? If it needs replacement, what is the best option? Carl's all Aluminum?

dr bob

There's some stoooopid stuff to think about. Like the cap, the plastic drain plug, leaking hose clamps and fittings that were R&R's during the radiator refit (??) Not clear in your post that you just drained the coolant from the radiator or might have done some wok while it was drained. For sure that plastic drain is a too-frequent problem when folks feel the need to actually tighten it; there's an o-ring that does the actual sealing, so it just needs to be snug enough to not fall out.

---

Often, after a coolant change, I go drive the car a bit, then come back and add a quart or two to the reservoir when it's alll cooled off again. There are air pckets in the system that don't get refilled until the engine is running a bit. Top of the water bridge is one, heater core is another, top of the radiator if the vent hose isn't routed perfectly. Last time, a few weeks ago, the drop in level was enough to set the coolant level warning light.

auzivision

My coolant system hasn't been touched for months since my car has been on stands all year. I've cleaned and dried all the areas, and it's definitely leaking at the plastic end cap to metal junction. I too first thought it was just the drain plug, but the area around the plug is clean and dry and a half inch to the left is a drip.

This photo is from a few weeks ago before any driving or cleaning. I checked the drain plug.. lossen and resnugged. Thought that fixed it until I went for a run to settle the suspension and noticed a few more drips when I got home.



I’ve found a small leak way up high near the upper hose, but it’s dry between hose and leak. I think it’s leaking out there and following the seam to the bottom.

I put about 150 miles on the car in the past couple days and really haven't lost a measureable amount of fluid, but my concern is if fluid can get out... then air can get in meaning it might not automatically draw fluid from the reservoir.

I put a bowl under it to see how much it leaks tonight.

I did find a thread on how to repair these as well as about the C&R setup. I’m leaning towards the Carl’s, just hope I can get one in time for SITM.

JHowell37

Auzivision, the seal between the aluminum radiator and the plastic end tank is usually what fails leading to the leak you have pictured. So your picture/problem is of the "usual" failure. The tank and seal are available from the usual suspects. About two years ago, I did a write up showing how to replace the tank with common tools, and without breaking the aluminum tabs.

daveo90s4

Easiest (and probably cheapest, fastest and most simple) fix is to buy a new plastic end tank and gasket and get a decent radiator shop to install it - and flush the radiator too in the process. This assumes that the bent clips will survive another bending and if it's not been done before they most probably will.