The SE is losing a lot of coolant very suddenly and I can't see where. No smoke out the tailpipe, no puddle under a standing car, no pressure in the header when I get home. Of course, nothing leaks and it builds pressure when I 've got the hood up!

 

heater core mabey? look under your carpet. just a suggestion.

 

could be a bad radiator cap letting all the fluid push out into the over flow then it getting too full after presurizing forcing it to spill out on the road a good suggestion is to loosen the cap about a half turn until it wont seal like its supposed to then take it for a drive be easy on the throttle though and see if your still losing coolant i did this about a year ago and made it 3oo miles back home. The reason why it works is it doesnt let the radiator pressureize and force the coolant out take extra water with you just in case if this works chances are you may have a bad cap or an internal problem with a water seal it would be the equivelant of a blown head gasket on a piston engine Do Not Be Too Hard On The Throttle Though

 

I've got some bad news if I'm correct about the cause. There is a small leak on one of the orange coolant seals. It is near the water port of the rotor housing (near the intake manifold). The engine is pulling a vacuum here and it happens to be where a lot of radiator sealant crap tends to settle because there is little flow in the this area.

You say this is an SE engine, right? The water ports on GSL-SE rotor housings were not drilled so there is even less flow in this area than on carbed engines. I have a set of RE-SI rotor housings which is the J-spec version of the GSL-SE (it came in the later HB Cosmo). The front rotor broke an apex seal at 5.5mm due to inadequate lubrication most likely caused by a minor coolant leak in that area. The cause of the coolant leak was pitting of the aluminum, which was caused by the PO's use of radiator sealant or not changing antifreeze often enough, or using more water than anitfreeze, or a combination of all three.

There was a thin green circle of hardened coolant most of the way around the side plate between the combustion chamber and orange coolant seal.

I can't think of anything else. bliffle, how old is your engine? Maybe it's time for a rebuild (I say that like it's a good thing).

 

2nd this, would be on the passenger side, you can sometimes feel wet carpet up near the unit if it is leaking. Bad heater core can put bubbles in your coolant system too.

 

correct me if im wrong but if there was vaccume in that area then wouldnt he be able to do my trick and still find the same problem? Only reason why i ask is cause if its on the exaust side then wouldnt the leak would force air into the coolant side of the system causeing bubbles to come out of the top of the radiator like a blown head gasket. i am still learning about these rotories so im just throwing an educated guess out there but if he does my trick and there is vaccume there then it will pull the fluid in and still cause low coolant levels? Please Correct me if i am wrong.

 

sorry about the spelling im on a laptop i am not used to

 

Engine has 160k and I adopted this orphan with 130k. always use MMO or 2-cycle, new radiator, waterpump, tstat, radcap, hoses this year.

Drove 2 blocks and stopped, looked on ground underneath where it was leaking a puddle on car centerline at front wheel axis. Seems like bottom of radiator where drain plug is.

I'll try the loose radcap stunt in the morning.

The carpet isn't wet, but the first time this happened was a couple days ago when I turned on the heater for the first time this fall.

I never get more than a wisp of smoke out the tailpipe on this car. It doesn't flood and starts easily unless the plugs are shot. Seems to have good power.

 

when you replaced the radiator, did you "burp" the system properly?

 

Yes, And that was 5 months ago.

 

Radiator is OK, hoses are good. Waterpump is about 6 mos. old.

No coolanr loss this morning after I had the heater dial on the dash dialed all the way closed. I'm concluding that it's a bad heater core. The leaking fluid must find it's way forward to make the puddle, somehow.

Do I have to remove the entire dash to replace it? Or should I just leave heater off (and/or install valves on the heater hoses)? I don't need it.

 

If you don't need the heater at all, and don't care, you can bypass it entirely where the heater hoses connect at the firewall side of the engine bay.

 

I can, and I may, even if as an experiment. But will it have an adverse effect on coolant flow?

Anyhow, has anyone replaced a heater core, and was it a dreadful job?

I ask because the windshield fogged up like crazy last night during a rainstorm (so I bought a 4" squeegee today).

 

160... bout time for a rebuild.

 

When the heater is turned off, the core is bypassed. Removing it simply does it on a pemanent basis. The Haynes manual for the 2nd gens has a very good section on removing the dash. They are quite similar between the 2 gens. I never had to put one back together in a 1st gen, not sure if it can be done without removing the dash or not.

 

The heater core is a hassle to replace. It can be done without removing the dash. The fogged up windshield is another symptom. There is a control valve on the driver (left) side, just above the gas pedal, which can leak also. If you remove the 2 hoses on the firewall and connect them together the coolant flow will be fine.

To get to the heater core remove the glove compartment, left side air duct, blower motor, and all the cables, wires, and hoses connected to the heater core box. With some wiggling and much cursing the heater core box will come out the right side. Disassemble the box and replace the core. It sounds easy. It's not. I'll post a few pics if you need them, but a detailed write up would take more time than I have right now.

 

It was the water pump. And that puppy was only 6 months old. got it from rockauto.com, so I sent them a complaint email and they said I should return it to them and they'd replace it. But I already got a good replacement from Kragens for $43, so if I send back the rockauto pump all I do is get a new replacement pump for my $5 postage and my time. So I'll just toss the defective pump.

The old pump was covered with white powdery residue (presumably from evaporated anti-freeze) and there was a squeaking noise from the front (which I had thought was an alternator bushing going out).

I would have caught this sooner but I couldn't believe a new pump would be defective.

 

Send it back and make a couple bucks off selling the replacement, or keep it for future use. You already payed for it, you might as well get a new one for free.