frustrating coolant problems?!

Ive got an 89 B2200, the truck recently started leaking antifreeze somewhere from the back of the engine still not sure exactly where its coming from?? At the same time my heater is blowing cold air. No matter how long i drive it wont heat up. I also noticed when the truck is idling it will rev up and then down constantly. I'd appreciate any information on this A.S.A.P Its too cold in Montana for no heater lol! Thanks

Don't hold me against my word for it, but from my past memory, I believe the onlt thing that relates to coolant in the rear of the engine is lines that go to the heater. Right behind the valve cover, it should be a hardline. Check the mating end of the hardline and the hoses back there.

Don't believe I can help you with the other problems you have, sorry!

right under the intake butted right up to the head is a steal line. on each end of this line there is a hose. check that hose on the back. also you might not have heat cause theres not any coollent in the system. fix the leak and most likly you will fix the heat also check the heater core hose's there back there to.

Thanx for the info guys. I'll double check all the lines tomorrow, but any clues why the engine revs itself up and back down again? Any suggestions always appreciated

We say this so often it sounds like a stuck record, but the #1 reason Mazdas idle poorly is vacuum leaks.All that pollution crap on the pass.fender well has vacuum hoses going to and from.By now they are all old and brittle and they leak.Check ur vacuum hoses for leaks and replace the ones that are.Idle problems should go away.If they dont,u have a solenoid on the pass, side of the carb that may be bad. It controls ur idle speed. BJ

Yup, it's too cold in Manitoba for no heater either... and I'm closer to the Artic circle than Montana. LOL !!

Sounds like you have a leak where the coolant lines connect with your heater core... and that would explain why you have no heat.

I also recently had a heat problem... and after flushing the system, changing the thermostat (180F rather than 192F), as well as adding fresh antifreeze... I still have don't have good heat. I think my heater core is plugged up 'cause the engine temp goes up like it should but I only get a little heat, which I'm currently supplementing with a 12V heater. Oh well, I guess I'll be changing the heater core come spring.

If you need to change the heater core check the link below.



Concerning the plugged heater core, here is some info I found in the 'net.

If you're so inclined, you can flush your cooling system at home using a garden hose. Or, if you have an air compressor, you can do a more effective, high-pressure flush by using a flush gun. Some people flush their cooling system with the engine running, but if you're doing a high-pressure flush, be sure to shut 'er down.

The recommended approach for the flush is to remove the out-take hose that leads from either the intake manifold or a cylinder head to the heater. Then send the fresh water in through a filler cap. This way, you'll flush both the radiator and the block, as well as the heater.

Has anyone used a "flush gun"? What does it look like? Please share your experiences.

Happy trails !!

check all the frezze plugs, heater hoses, heater core.

Sounds like a plan... but how do you check the heater core without removing the entire dash?

Cheers !!

My dash is out, ive been fiberglassing it and getting ready to cover it in tweed, so with that aside how do i check the heater core to know if its bad?

Covering your dash in tweed? Cool !!

As for checking if the core is bad, my only comment is... when in doubt, replace.

A brand new core will solve any heating issues you currently have!!