By "inline" do you mean the ones that go on the lower rad hose ? They don't tend to bake the hoses and make them brittle over time ?

Roj

The block heater on them goes inline with the oil cooler on the side of the block and the hoses are a different composition (silicon innards with a rubber outside) but its not like the inline heater is making it grossly warm in there.

Given the sequence of events over the last week, I'd suggest changing the odd rad hose, if it did in fact "bake" it, is a damn sight easier than what you've tried to do...

Now that's a keenly insightful observation and certainly NOT stating the obvious.

im pretty sure my 93 engine is from 93.. and my car is from 88 and nothing weird, just tapped the frost plug in, worked like a charm... ?

Originally you said you had no issues installing your block heater in a '93 block. Now you're saying it was a frost plug. Which is it ?

I desperately need help installing a frost plug. See my new thread. "I'm about to smash something".

He tapped the frost plug in to disloge it, Roj. Don't be difficult, now...

These heaters are fine with hoses etc. They will not bake anything, the hose itself can handle a fair bit of heat (that's the point) and the heater itself is incased in a separate can that holds the element. The coolant in the hose is then brought up to temperature and circulates. Most new cars that have block heaters as an option use this type of heater instead of the frost plug style.

I did the calculations for your frost plug and would support what Ian said - you are dealing with a 1.6 thou fit - in the world of machining, that's pretty much an interference fit and will not work. BFH in this case will damage something. About a 5 thou fit on a pressed part like a frost plug would be insane to fit as well. Get the stock plug.

Craig

Found this old thread and wanted to ask about installing a circulating style heater in an 86 740 NA. I bought a Zerostart tank style circulating heater but am unsure where to plumb it in.

From looking at the instructions the inlet goes as low as possible on the block, and the outlet should go to the heater inlet hose so it circulates through the heater core and then back to the engine. Does this make sense?

After reading through this thread I don't know if I want to be pulling out frost plugs as the instructions suggest so trying to figure out where to pipe the inlet to. Also if I mount the heater on the passenger side fender down on the frame rail would I need to run a hose up and around to tee into the heater hose as the line that comes off the side of the water pump is hard piped around the side of the engine.

I hate to say it but once I got looking at installing this my first thought is to take it back and get the heater that splices into the lower rad hose. I don't think these work as well as the tank style at getting the whole system hot?

The final thought is why I am doing this in the first place as the car already has a block heater? My oldest daughter who is driving this car is bitching about loosing her spot in the garage and has to park outside now (wah!!). I am trying to get it so the car is warm right away, even though we know Volvo's heat up quick we're talking whiny teen here....

I didn't see your post here first...just tell your daughter to buck up for heaven's sake. Last winter I drove my 122 without a heater at all. I would have to drive home with the windows down at -20 after a hockey game so the windows wouldn't fog up. How I never got pulled by the local constabulary I'll never know.

Sorry, I should have edited to show the move to another thread. I hear you on what "should" be said, maybe I'll get the chance to explain my situation some day, just don't want to get in to it on a public forum.

come on now, we girly types are a fragile breed!

I'd go mad without my heated seats! No heat would be very very bad!!!!

ps. you boys remember, you're furnaces, yet the lady types are always complaining they're cold. differences between the sexes I guess *shrug*