Hi All,
I am considering putting in a used engine (since I have a blown head gasket) in my car. Got a number of questions that I'd welcome input on:

1. Looking online I see that Mazda 3, Mazda 6 and CX-5 engines are listed as interchangeable. Are these truly identical or are there certain nuances that one needs to be aware of?
2. Is there a list of other parts I should definitely replace (my car is at 90K miles) while engine is being swapped? I can certainly think of basics like spark plugs, new belts, water pump, etc, but wanted to see if there is a list of things that are recommended (thing that typically go bad when cars reach certain milestones). I am thinking it may make sense to address a number of things while the engine is out.
3. The PCM on my car doe not have most recent software on it (per my dealer). Does it need to be flashed as par of the engine replacement job? If so, can any car mechanic do this as long as they have the right equipment?
4. I read that on a newly built engine one needs to pay attention and reduce the risk of a dry start damaging a newly built engine by priming the oil system. Is that true, if so, how is it done?
5. Finally, there is a bunch of used engines online offered by a number of companies. Some offer 2yr 3 yr warranties for extra $, some say the engines are inspected. Is there one or two reputable companies out there when it comes to buying a used engine? Are there any companies that sell re-manufactured engines for CX5?

Many thanks.

 

What size is the engine which came in your CX-5?

 

Jasper is a well known engine rebuilder for american cars, I assume they have engines for Mazda as well. I have had to get replacement engines a couple of times, they just came from autt recyclers, or junkyards as we used to call them. Both engines served me well. If you go that route, I'm willing to bet you'll be told the engine "only has 30,000 miles on it." By some miracle all cars seem to get totalled at 30,000 miles. ;-) If a local shop does the swap, they'll probably crank the engine with the spark plugs out, to get oil circulating in the engine before the actually start it. Remanufactured engines, are generally lubed in critical areas, camshaft, crankshaft, etc. to prevent a dry start. But most shops will likely crank them with the plugs out, just to be sure.

 

Here in the U.S., a very good resource for used engines (and pretty much any other part) is www.car-part.com

 

2.5 liter

 

thanks for the input. I had looked into Jasper. Unfortunately, they do not have these Mazda engines (yet).

 

A mechanic I talked to said if "let me look into it, you may be lucky and may need a gasket replacement job which may be more cost effective than an engine replacement". He said the piston head caps may need some rework as part of that.

When an gasket is blown what is the absolute minimum damage that can happen? We did not have any white smoke coming from the exhaust, did not experience loss of power, the oil and coolant levels were normal. The only thing that did not work is the heater inside the cabin. The car exhibited a tiny bit of stalling when idling (after the check engine light came on).

One more question: The car has been sitting in this condition for over 3 weeks now. I heard that the coolant could by now have damaged the bearings. Is this a true possibility?

 

You may just need to get the head milled to make sure it's flat, a valve job is an easy thing to do with the head off. That may be it.
There could be water in the oil, but that doesn't mean the bearings are sitting in oil. The residual heat when the engine shut down would likely evaporate off any water that might have be circulating in the oil. If it was a small leak, the coolant and water may have just been going out the exhaust pipe and not creating enough steam to be visible. The mechanic you mention seems to be giving you good advice.

 

In 56 years of driving, I've blown head gaskets on three cars: a 1965 Mustang, a 1981 Wabbit Diesel and a 1986 4Runner. None of them required engine replacement and all ran great after repair (well except the VW, but it ran as well as it ever did until the head gasket blew two more times and I junked the thing in disgust).

 

You've got me beat by a couple of years, I've "only" been driving for 48 years, and in that time I've amassed something over 2,000,000 miles. There was one vehicle which I thought I'd blown a head gasket on (an iron-blocked V6 with aluminum heads) due to some coolant showing up in the oil, turned out to be a twenty-five cent "O"-ring for the coolant bypass in the timing chain cover. I did the head gasket job over a long weekend and then took a 2,500 mile trip immediately thereafter. The coolant loss didn't abate one bit; that's when I did a deeper dive into how the coolant was routed in that engine and found the culprit. Long story short, over two-million miles, no head gasket failures.