HT4100 4.1, 4.5, 4.9 Discussion, Losing coolant when the heat is turned on. in Cadillac Engine Technical Discussion; Hello,
I have a 1993 sedan deville, haven't had a problem with the coolant levels until yesterday. I ran the ...
I have a 1993 sedan deville, haven't had a problem with the coolant levels until yesterday. I ran the heat for the first time this year, nothing but cold air for about an hour of driving. I checked the fluid levels when I got home. I ended up putting 3/4 of a jug of antifreeze in the car and a bottle of bars anti-leak pellet stuff. I drove the car with the heat on for 25 minutes and re-checked, it was down enough to have to fill the rad. cap. topped off and drove to school this moring (60 miles, no heat on), levels are fine. Is this a heater core issue or more likely a heater hose issue? Thanks for your help.
P.S. No warning lights, overheating, rough running of any type and no wet carpets, just the smell of anti-freeze every now and again from outside the car.
You're going to have to find the source of the leak, which shouldn't be too hard since it sounds bad. If the leak is big enough, your cooling system will suck in air, causing an air bubble, and hence, no heat.
Look under the car for the antifreeze drips. If you don't have wet carpets, then it's probably not a heater core, but it could be one of many things (leaking hose, water pump, cracked radiator, etc.)
the way I look at it the core and cap are thirteen years old, besides it's less than 40$ for both out the door. I just got back from school (60 miles, with no heat on) without a drop in level. So I'm thinking core or hose, I hope core the hose looks like a nightmare to replace. What's this control value mention earlier?
Automobile(s): 1995 FWB 100,*** miles CURRENT. 1991 Seville 175,000 SOLD
Re: Losing coolant when the heat is turned on.
Turning heat on has no effect on the flow of the coolant inside the system. It just turns a fan on to create an air flow through the heater core.
The potential points of leaks are cracked radiator end tanks, a tiny crack on the heater valve (the plastic T), hose connections and the heater core. The reason you do not have heat is most likely clogged heater core. Mine started leaking AFTER I flushed and back flushed it. So I had to replace it with an aftermarket allmetal unit ($30). Not an easy job, but doable. A leaking heater core will eventually drip on the carpetor and even steam inside the cabin.
I noticed coolant fountaining from a tiny crack on the heater vave (T) only after increasing RPMs to some 3000 with open hood (gear selector in P).